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NAKIVO Blog > Hyper-V Administration and Backup > Full Overview of Hyper-V Dynamic Memory Best Practices

March 25, 2019

by Jessie Reed

Full Overview of Hyper-V Dynamic Memory Best Practices

Hyper-V Dynamic Memory was first introduced in Windows Server 2008 R2 with SP1. Prior to its release, a Hyper-V virtual machine (VM) would start and run with the full amount of RAM assigned to it, which resulted in memory overuse and affected overall VM performance. Moreover, the amount of available VM memory could be changed only when the VM was turned off. Thus, it is reasonable that static memory allocation had to be replaced with dynamic memory allocation and the Hyper-V Dynamic Memory feature was introduced.

Today’s blog post includes a full overview of the following Hyper-V Dynamic Memory Best Practices:

What Is Hyper-V Dynamic Memory?

Hyper-V Dynamic Memory is a feature that allows you to dynamically allocate memory resources to the VMs running in Hyper-V environments. This functionality reclaims a part of unused memory from VMs that don’t need it at that particular moment and then reassigns the reclaimed memory to other VMs that actually require it.

With Hyper-V Dynamic Memory, you can specify the amount of startup memory that the VM can use, set the range of available physical memory for a specific VM, and determine the VM’s priority for memory allocation. Physical memory can be efficiently and dynamically assigned to the VM on an as-needed basis and with minimal performance impact. As a result, you have more granular control over memory usage and enhanced resource optimization.

Advantages and Disadvantages of Hyper-V Dynamic Memory

Hyper-V Dynamic Memory is a useful feature which offers a lot of advantages, such as:

However, Hyper-V Dynamic Memory also has a number of disadvantages, which can negatively affect VM memory performance. They include the following:

Hyper-V Dynamic Memory Settings

Hyper-V Dynamic Memory includes five VM settings which can be configured in Hyper-V Manager . For that purpose, open Hyper-V Manager, select the required VM, click Settings , and choose Memory. You will see the following:

Hyper-V Dynamic Memory Settings

However, before you can start configuring Hyper-V Dynamic Memory settings, it is first recommended that you get to know how these components work and what benefits they can provide. Let’s take a look at each of them.

Startup RAM

This Hyper-V Dynamic Memory value defines the minimum amount of physical memory a selected VM can use during its startup. Startup RAM should be high enough to enable the VM to start rapidly and without interruption. Note that startup RAM cannot be changed when the VM is running.

Startup RAM (Hyper-V Dynamic Memory Best Practices)

Minimum RAM

This Hyper-V Dynamic Memory value determines the minimum amount of physical memory that should be assigned to the VM after it has started. If other VMs require additional RAM, the Hyper-V host can start reclaiming unused memory from this VM until the minimum RAM value is reached. Note that the value can be set as low as 32 MB but it can’t be higher than Startup RAM. Moreover, you cannot increase the minimum memory while the VM is running or paused, but you can decrease it (e.g. you can change the minimum RAM value from 512 MB to 64 MB).

Minimum and Maximum RAM (Hyper-V Dynamic Memory Best Practices)

Maximum RAM

This Hyper-V Dynamic Memory value specifies the maximum amount of physical memory that the VM can use. Note that this value cannot be lower than the assigned Startup RAM but can go as high as 1 TB (1,048,576 MB). Moreover, you cannot decrease the maximum memory amount while the VM is running or paused, but you can increase it (e.g. you can change the maximum RAM value from 512 MB to 2048 MB).

Memory Buffer

This Hyper-V Dynamic Memory value determines the percentage of physical memory that should be allocated to the VM as a buffer. Memory buffer is a portion of physical memory which is set aside for the VM based on its memory needs. To calculate the memory buffer, you need to use the following formula:

Amount of memory buffer = how much memory the virtual machine actually needs / (memory buffer value / 100).

By default, the memory buffer value amounts to 20% but it can be set up to be as low as 5% and as high as 2000%. You can change the memory buffer value at any point, even while the VM is running.

Memory Buffer (Hyper-V Dynamic Memory Best Practices)

Memory Weight

This Hyper-V Dynamic Memory value specifies the priority of the selected VM compared to other VMs on this host. Based on this order of priorities, you can determine how to distribute the available memory among multiple VMs running on the same Hyper-V host.

Note that if the VM priority is set too low and the amount of available physical memory decreases, there is a risk that this VM will not be able to boot. You can change the memory weight value at any point, even while the VM is running.

Memory Weight (Hyper-V Dynamic Memory Best Practices)

Hyper-V Dynamic Memory Best Practices

To achieve high performance and improve memory utilization in Hyper-V environments, it is recommended that you adhere to Hyper-V Dynamic Memory best practices.

The Hyper-V Dynamic Memory best practices listed below can considerably improve VM memory performance and your overall experience in Hyper-V environments.

Enable Hyper-V Integration Services

Hyper-V Integration Services is a set of utilities which allow for improving VM performance in Hyper-V environments. Each Hyper-V Integration Service must be enabled in both the host and guest so that they can properly function and deliver services as required. By default, all Hyper-V Integration Services, except for Hyper-V Guest Service Interface, are enabled on the guest OSs.

For Hyper-V Dynamic Memory to function effectively, make sure that Hyper-V Integration Services are upgraded to the latest version and that the guest operating system supports the Dynamic Memory feature. Otherwise, Hyper-V may experience issues because memory cannot be provided dynamically and memory demands cannot be addressed properly.

Since the release of Windows Server 2016, Hyper-V Integration Services and corresponding updates can be installed through Windows Update. Therefore, you should configure your VMs to receive updates in order to make sure your Hyper-V infrastructure uses the latest version of Hyper-V Integration Services.

Monitor memory usage and resource allocation

Currently, there are many Hyper-V management tools on the market which allow you to monitor memory usage and resource allocation in Hyper-V environments. With Hyper-V Dynamic Memory enabled, it is possible to overprovision RAM and completely run out of memory. Thus, it is recommended that you keep track of the RAM that you allocate to various VMs on your Hyper-V host.

For this purpose, you can use native monitoring tools or purchase third-party software. For example, you can check the VM memory state through the host in Hyper-V Manager or the guest VM in Task Manager.

Hyper-V Dynamic Memory Best Practices in the Hyper-V Host

This way we can monitor how memory resources are used within the system. However, note that Hyper-V Manager and Task Manager demonstrate different outputs for memory usage. The guest monitoring tool doesn’t show the actual results because the guest VM believes that the total amount of memory assigned to the VM is actually in use by its driver. In reality, the host is generally more aware of the way memory is being distributed to VMs within the infrastructure. Unused memory is actually reassigned to other VMs and this is reflected in Hyper-V Manager.

Take into account Startup RAM

Setting up Startup RAM higher or lower can considerably affect Hyper-V performance. You should increase the Startup RAM to ensure that the OS and the applications running on it start as required. This is due to the fact that Windows requires more RAM during startup than when the OS is idle.

Moreover, during install or upgrade operations, the amount of RAM available to the guest OS is equal to the Startup RAM value. Therefore, before performing installation or upgrades, it is critical to ensure that the Startup RAM value meets the minimum memory requirements of the selected OS.

Note that if the Startup RAM value is set too high, this might also negatively affect Hyper-V Dynamic Memory performance and overall memory usage. Thus, it is recommended to assign 512 MB as the Startup RAM value for the guest OS so that it would boot without interruption.

Don’t forget about memory leaks

When setting Hyper-V Dynamic Memory limits for a particular VM, it is critical to keep in mind that your infrastructure may be subjected to memory leaks. Memory leaks imply the gradual loss of available memory as a result of incorrect memory allocation. It usually occurs when an application fails to release memory which was provided only for temporary use. If the issue is not detected before any serious damage is done, the OS memory can become exhausted and the application will eventually fail.

In order to mitigate negative effects of this issue, it is recommended that you install a monitoring tool (e.g. RAMMap) and scan the entire infrastructure for any inconsistencies and detect unusual cases of memory usage by running applications. Also, such tools can help you determine the minimum and maximum RAM values which would be most appropriate for this particular VM.

Configure the Maximum and Minimum RAM values

To ensure that Hyper-V Dynamic Memory functions as required, it is recommended that you determine limits which the system cannot exceed. This way, memory utilization within your infrastructure is effectively controlled, meaning that the VM won’t consume too much or too little memory.

Carefully set the Memory Buffer value

One Hyper-V Dynamic Memory best practice is to assign the appropriate Memory Buffer value, which specifies how much extra memory should be made available for a selected VM. If the Memory Buffer value is set high, this extra amount of memory is generally used for file caching in large-scale VMs and streamlining I/O operations within the system.

At the same time, the Memory Buffer value should be set low if there is a running application that requires a large amount of physical memory. With the reduced Memory Buffer value, you can be sure that the available memory is not completely consumed by a single VM.

Moreover, if a large amount of memory has already been assigned to the VM, it is unlikely that it will ever require extra memory. Thus, it makes more sense to share unused memory resources with other VMs which need it more.

Update Hyper-V hosts when needed

In order to keep your Hyper-V environment stable and secure, make sure that your Hyper-V hosts install all updates and security patches when required. The main purpose of Microsoft updates and security patches is to deal with the issues that have been identified in the system. For example, an issue with Hyper-V Dynamic Memory that prevented Hyper-V VMs from getting additional memory was detected in Windows Server 2012 R2. Even though the feature was enabled on the VMs, it still continued to fail. Due to this fact, Microsoft released the hotfix in order to remove the issue and ensure that the functionality works as required.

Detect performance changes in the course of the day

Production workload increases considerably during working hours, which eventually affects Hyper-V performance as well as resource allocation and memory utilization. As one of Hyper-V Dynamic Memory Best Practices, it is recommended that you monitor the changes in memory usage throughout the course of the working day. By detecting when the cycles of high and low memory usage typically occur, you can learn how to use Hyper-V Dynamic Memory to your advantage.

Enable Hyper-V Dynamic Memory when it is actually required

Even though Hyper-V Dynamic Memory is an extremely helpful feature which improves the use of physical memory, there are some cases when static memory allocation is the preferable option. Thus, you should consider whether Hyper-V Dynamic Memory needs to be enabled on a particular VM or not. For example, some applications perform better if they have a pre-determined amount of RAM which they can use without interruption. The amount of pre-assigned RAM stays the same despite the fluctuations in memory demands.

Thus, it is recommended that you plan ahead how physical memory will be distributed in your Hyper-V environment so as to prevent running low on RAM and avoid application failures in future.

Use Hyper-V Dynamic Memory with compatible applications only

Before installing any application on your Hyper-V host or guest, make sure that this application can be used along with Hyper-V Dynamic Memory. To check such information, it is recommended that you first read product support documentation to know about its functions and system requirements. Such precautionary measures can help you avoid any issues with memory usage and allocation which might occur.

Wrapping Up

After learning about Hyper-V Dynamic Memory best practices, you can start using physical memory more efficiently and securely. However, your virtual infrastructure is still exposed to various dangers and threats which can undermine its performance. To ensure safety of your virtual environment, using a data protection solution is the most feasible option. NAKIVO Backup & Replication is a reliable, effective, and affordable solution which provides VM backup, replication, backup to cloud, backup copy, site recovery and a rich set of features.

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Configure at least the required amount of memory for a virtual machine running Windows 8.1 and enabled for Dynamic Memory

Applies to: Windows Server 2022, Windows Server 2019, Windows Server 2016

For more information about best practices and scans, see Run Best Practices Analyzer Scans and Manage Scan Results .

In the following sections, italics indicates UI text that appears in the Best Practices Analyzer tool for this issue.

One or more virtual machines are configured to use Dynamic Memory with less than the amount of memory required for Windows 8.1.

The guest operating system on the following virtual machines might not run or might run unreliably:

<list of virtual machines>

Use Hyper-V Manager to increase the minimum memory to at least 256 MB, and the startup memory and maximum memory to at least 512 MB for this virtual machine.

Increase memory using Hyper-V Manager

Open Hyper-V Manager. (From Server Manager, click Tools > Hyper-V Manager .)

From the list of virtual machines, right-click the one you want, then click Settings .

In the navigation pane, click Memory .

Change the RAM to at least 512 MB.

Under Dynamic Memory , change the Minimum RAM to at least 256 MB and the Maximum RAM to 512 MB.

Increase memory using Windows PowerShell

Open Windows PowerShell. (From the desktop, click Start and start typing Windows PowerShell .)

Right-click Windows PowerShell and click Run as administrator .

Run a command similar to the following, replacing MyVM with the name of your virtual machine and the memory values with at least the values shown below.

Submit and view feedback for

Additional resources

Managing VM RAM better with Hyper-V dynamic memory

Andrew Zhelezko

When it comes down to Hyper-V resource management, you’d better be sure about utilization in your own environment. There is some specific monitoring software, allowing you to get an overview of system consumption and even perform capacity planning for future, but sometimes it might not be enough. Built-in Hyper-V features, on the other hand, that let you care about the future right at the configuration stage. Hyper-V dynamic memory is one of these technologies, and below, you’ll find out how you can manage your Hyper-V VMs better with it.

Dynamic memory is a Microsoft Hyper-V feature first introduced in Windows Server 2008 R2 SP1 and expanded in Windows Server 2012. This technology allows hypervisor to handle RAM consumption by host VMs in a flexible way, if possible. For example, hypervisor can dynamically add more RAM to a VM when the guest-OS needs it, or to reclaim excess back when a VM goes idle.

Even though RAM is not as much of an issue these days and pricing for RAM modules is noticeably dropping over the years, sometimes you can find this technology very handy. What if you’re operating with a limited budget or using old servers that can’t be easily upgraded and given additional RAM? In addition to that, this technology works perfect with a great number of VMs, keeping overutilization under control, allowing you to forget about wasting resources and providing better visibility towards your system. It can be especially helpful when you have a lot idle or low-loaded VMs (ex. VDI environments).

Let’s look at Hyper-V dynamic memory settings and see how we should set them up.

All these dynamic memory settings should be configured within VM settings in Hyper-V Manager. Keep in mind that to enable or disable dynamic memory, the VM must be powered off at the moment. So once you create a VM or edit an existing one, you’ll select the amount of RAM for a VM and there are two options: Assign a certain value (static) or enable dynamic memory and let the hypervisor re-assign it on-the-fly. With the static option, the amount remains the same regardless if a VM is starting up, idle, performing an action or shutting down. While with dynamic memory, the amount is adjusted according to VM experience.

Hyper-V dynamic memory settings

When you decide to configure dynamic memory, there are few values you should set up.

Startup RAM . The amount of RAM assigned to the VM during its startup. This value can be the same as the “minimum RAM,” or more — up to the “maximum RAM.”  The startup RAM value can’t be configured when a VM has been powered on.

Once the VM boot is complete and the hypervisor started, it will try to use the amount of RAM configured as the minimum RAM.

Minimum RAM . The minimum amount of RAM that the host should be trying to assign to a VM, when it’s booted. When multiple VMs are demanding memory, the Hyper-V host can reallocate RAM away from the VM until this minimum RAM value is met.

This setting can be only reduced (down to 32 MB with 2MB step), not increased while the VM is running. Be careful with that, as the changes take place immediately and you will have to power the VM off if the value is occasionally set too low.

Maximum RAM . The maximum amount of RAM that the host provides to a VM.

This option can be only increased, not reduced while the VM is running. There is a 1TB maximum you can allocate as per Hyper-V in Windows Server 2012 R2 limitation.

All values above can only be configured with odd numbers in increments of 2MB.

Memory buffer . The percentage of memory that Hyper-V should allocate to the VM as a buffer.

The value can be configured within 5-200% range with 20% set by default.

A Hyper-V host uses the current VM demand for memory to figure out how much memory for the buffer it should be reserving. For example, for a VM with a current RAM consumption at 1TB, Hyper-V is keeping a 20% buffer and allocating the VM 1.2TB of RAM.

Memory weight . The priority you’re setting for this VM compared to other VMs running on the same Hyper-V host.

Hyper-V dynamic memory of powered VM

Keep in mind that memory adjustment is fast but rather conservative. It means that a virtualization host doesn’t provide all the resources at once even if it can do that right away. Instead, it would be trying to keep things according to the actual RAM consumption and the memory buffer settings.

To show how exactly it works, I’ve set up a test VM (Windows 8.1 64-bit, Veeam Backup & Replication v9 pre-installed) with the parameters from the figure above. Startup RAM – 2GB, Min RAM – 32 MB, Max RAM – 1TB, memory buffer – 20%. Then I launched the VM and found out that during the initial OS boot, it was assigned with 2GB RAM as expected.

Hyper-V dynamic memory. VM is booting

Once the system booted, I noticed the hypervisor began to regain RAM from the VM, which was idle. RAM was going down and reached 698 MB at rest.

Hyper-V dynamic memory. VM is idle

Then, I started Veeam Backup & Replication application and ran the backup job, just to bring some workload to the VM. As expected, the VM demanded more RAM from the hypervisor and the hypervisor gradually allocated more RAM to it.

Hyper-V dynamic memory. VM is under workload

I’ve also been checking the RAM value from the guest-OS and noticed that the internal Task Manager might be reacting slow to the RAM amount change or just showing an incorrect value. That’s why it is better to trust Hyper-V Manager information or use a dedicated Veeam Task Manager for Hyper-V for CPU and RAM monitoring in the first place.

Veeam Task Manager for Hyper-V

Hyper-V dynamic memory is a great help for Hyper-V administrators. The technology allows to run multiple VMs with RAM overutilization and dynamically balance the resource consumption, according to actual VM load. Whenever you’re tight on RAM resources or have a desire to manage available computing resources better, you know what to enable.

Andrew Zhelezko

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Understanding Hyper-V Dynamic Memory (Dynamic RAM)

Etienne Liebetrau

Etienne Liebetrau

Running resource intensive applications on a virtual machine is a great way to ensure they do not consume more compute resource than is necessary, and the same physical machine can be used to run multiple discrete workloads.

A great example of this is generating reports in TMG Reporter ,  Sophos Reporter  or  WebSpy Vantage . The reporting process will increase the virtual machine's RAM and CPU requirements, but once the reporting workload is complete, the actual requirement drops back down again.

The two major hypervisors (VMWare and Hyper-V) have different ways of dynamically allocating more or less physical RAM to the virtual machines running on top of them.  Microsoft Hyper-V’s approach is to let the virtual machine and hypervisor communicate with each other, so that the RAM can be continually adjusted based on the virtual machine’s requirements.

This means that from the virtual machine's perspective, it will have different amounts of RAM depending on the workload. This article will focus on how this dynamic process affects what you see from the both the hypervisor and virtual machine's perspective.

Configuring Dynamic Memory

When editing the virtual machine’s hardware configuration, you specify the Startup RAM, and you also have the option of enabling Dynamic Memory. When this is selected you have the option to specify three additional fields.

Minimum RAM

Maximum ram, memory buffer.

what is assigned memory in hyper v

Startup RAM

This is the amount of physical RAM that will be allocated to the virtual machines at startup. Regardless of what the actual RAM demand is, the host will reserve this for the virtual machine.

From the virtual machine's perspective, the amount of visible RAM will never drop below the Startup RAM amount.

As the name implies, Minimum RAM is the minimum amount of physical RAM that the host will reserve for the virtual machine. Once the virtual machine notifies the host that its RAM requirement has decreased, it will start reducing the amount of physical RAM that is allocated, but never below this amount.

From the virtual machine's perspective, it will still see the Startup RAM amount.

Maximum RAM is the maximum amount of physical RAM that the host will allocate to the virtual machine, regardless of what the load is. Even if the virtual machine wants more, the host will never allocate any more RAM than this amount.

From the virtual machine's perspective, the visible amount of RAM will start increasing as the demand grows, but it will never exceed this amount. It is also important to note that the visible amount of RAM to the virtual machine will never drop below the highest amount allocated. In other words, the virtual machine will always see the 'high water mark' of RAM allocated to it.

The Memory buffer allows for instant RAM should the virtual machine need it. This 'excess' RAM is available before additional RAM is allocated by the host to the virtual machine.  The Memory buffer is relative to the current RAM allocation.

For example, if the current RAM allocation is 10 GB, a 20% buffer will keep 2GB of 'instant' RAM free. If the current RAM allocation is 5GB, only 1GB will be kept free. For more information, see the MSDN article What is the memory buffer when dynamic memory is enabled .

Note: These Dynamic Memory fields can be changed while a virtual machine is running. Minimum RAM can be decreased, Maximum RAM can be increased and the Memory buffer can be either increased or decreased. The virtual machine will become of aware of the new limits without needing a restart.

Monitoring Dynamic Memory in Hyper-V

Dynamic Memory introduces variable amounts of RAM allocation on both the host and the virtual machines. So lets first take a look at how the RAM allocation looks from the hypervisor's perspective.

System Center Virtual Machine Manager

SCVMM gives the most complete view of the Dynamic RAM picture.

what is assigned memory in hyper v

In this image, you can see there are varying amounts of assigned RAM to the three virtual machines.

The SCVMM view is great because it is complete and provides you with the total picture. It does however lag a little behind. The best place for more 'live statistics' are in the Hyper-V Management Console.

Hyper-V Management Console

The Hyper-V Management Console provides a simple and convenient real time view of the RAM assignment. It does not however give you the memory demand information. As such, is it not a great tool to determine the minimum baseline for your virtual machines.

what is assigned memory in hyper v

Performance Monitor - Useful Performance Counters

By using Performance Monitor  (Perfmon) on the host itself, you can get a very detailed live view of the Dynamic Memory picture. The key counters to use are:

Hyper-V Dynamic Memory Balancer

The Hyper-V Dynamic Memory Balancer counter gives you a view of how the host is doing from a memory perspective. In the image below, the host still has 66GB of RAM available to allocate based on demand. The current demand or 'pressure' from the virtual machines is 65. When the pressure gets to 100, the host is essentially out of RAM.

what is assigned memory in hyper v

Hyper-V Dynamic Memory VM

The Dynamic Memory VM counter gives you a view very similar to what we have seen from the SCVMM and Hyper-V Management consoles.

One counter that is very useful here is the Guest Visible Physical Memory . This indicates how much RAM the virtual machine has visible, and it also indicates the high water mark  for RAM demand. Perfmon also gives us the advantage of being able to track the RAM allocation on a graph.

Monitoring Dynamic Memory in the Virtual Machine

In a Dynamic Memory scenario, the virtual machine will be in one of three states.

Less than Startup RAM

More than startup ram.

At  startup, the virtual machine looks and behaves like a physical server with the Startup amount of RAM installed. The memory usage graph looks normal and from the Hyper-V console we can see that 4GB of RAM has been allocated.

what is assigned memory in hyper v

A few minutes after the machine started, we notice a spike in the RAM usage. What has actually happened is not that the RAM usage has gone up, but that Dynamic Memory has started reducing the amount of physical RAM allocated to the machine. Since the virtual machine will never report less than the startup amount of RAM, it still reflects the 4GB.

what is assigned memory in hyper v

You will notice however that usage is only at 70%. This is because of the memory buffer, if we increase or decrease the buffer size it will impact this percentage.

To simulate a sudden RAM increase, I am using a utility from Sysinternals called testlimit . When I demand an additional 2GB of RAM, the graph jumps. It then appears to level out even though the additional demand is still present. This is because more RAM has been allocated by the host.

what is assigned memory in hyper v

When the additional 2GB demand is removed again, the graph drops.

what is assigned memory in hyper v

Once the pressure normalises, the virtual machines goes back to only consuming the usual 2GB of physical RAM.

When I demand an additional 4GB of RAM above the baseline, it exceeds the Startup RAM. The virtual machine is then allocated additional physical memory from the host. At this point the installed memory count also goes up.

what is assigned memory in hyper v

Note that even after the load has been removed and Dynamic Memory has released, the physical memory and the installed memory still reports 6GB. As covered earlier, the visible amount of RAM will never drop below the highest allocated amount.

what is assigned memory in hyper v

Below is a 20 second interval Perfmon graph showing a trace of both physical memory and pressure from the host's perspective.

what is assigned memory in hyper v

You can see that when the pressure is raised, the RAM amount increases almost immediately. Once the RAM is allocated, the pressure drops a little. When the load is removed, the pressure goes way down, and when the pressure stays low for a few minutes, the RAM allocation drops. At this time, the pressure goes back to the standard count of about 60.

So how much memory is actually allocated and used?

This still leaves the question of how much memory is actually allocated and used? For this information, you can use another tool from Sysinternals called RAMMap .

In RAMMap, the counter to look for is called Driver Locked . At startup there is basically no RAM locked. Once Dynamic Memory steps in and releases the physical RAM, you can see the Driver Locked amount increases. At this stage the Total still stays the same.

what is assigned memory in hyper v

When we bump the load up again, the Total increases. Once we terminate the process, the RAM moves to being unused.

what is assigned memory in hyper v

When Dynamic Memory releases the physical RAM, the unused amount is now moved to Driver Locked.

what is assigned memory in hyper v

It is important to remember that the Driver Locked amount is an artificial lock on RAM that does not really exist for the virtual machine since it is not backed by any physical RAM from the host.

Making use of Dynamic RAM in Hyper-V is a great way to maximise the hardware you have available. Having a proper understanding of what the actual demands of your virtual machines are can help you tailor its RAM settings.

Realistic figures should be used when specifying the Startup and Minimum RAM amounts. If these are too low you will inevitably invoke the dynamic addition and removal of RAM all the time. Although this is not a problem, it does carry some overhead.

When looking at memory utilisation on the virtual machine it is important to remember the context in which it exists, just because it indicates a high percentage of RAM utilisation, does not mean it is consuming that amount of physical RAM.

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Memory Management, Requirements and Usage in Hyper-V

Table of contents.

Memory is the most precious resource in the typical virtualization host. It cannot be shared among virtual machines. The computing costs to compress or de-duplicate it are so prohibitive that neither is feasible.

Virtual machine density relies heavily on the amount of installed physical memory, but the financial cost of memory escalates quickly with higher chip capacities. Proper memory planning is absolutely essential to a successful Hyper-V deployment. In this article I’ll explain the concepts of memory in a Hyper-V environment to give you the necessary background to make those plans.

Hyper-V’s Memory Operations and Requirements

A hypervisor’s primary purpose is to control access to hardware, and that includes memory. It walls off the memory assigned to each virtual machine in such a way that the virtual machine “sees” its memory in the same way a physical machine views its memory. It is completely unable to access anything other than what Hyper-V assigns to it.

The technique that Hyper-V uses to achieve this is address translation . As you may recall from the introductory article on Hyper-V , the Hyper-V server role benefits greatly from hardware-based translation, called Second Level Address Translation, although it can perform it in software if necessary. 2012 R2 is the last server version that will include this software capability; Client Hyper-V has never had it. The following diagram provides a conceptual illustration of address translation:

what is assigned memory in hyper v

The guest operating system of each virtual machine believes that its memory address space starts at 0 and counts upward to encompass all available memory. When it passes requests for memory access through its CPU, the request is translated into the physical memory address behind the scenes.

Hyper-V’s memory assignment and tracking activity is not without its own costs. Hyper-V itself needs about 300 megabytes of memory for its own process. For each virtual machine, any memory amount up to the first megabyte requires 32 megabytes of overhead. Every gigabyte past the first incurs another 8 megabytes of overhead. All of this is in addition to the 512 megabytes that the management operating system requires (it will often use less, but it cannot be pre-estimated with any level of accuracy).

This means that the absolute minimum amount of memory that you should expect your physical host to be unable to utilize for virtual machines is 1 GB. In practice, it is commonly observed that other processes in the management operating system require even more memory to be set aside. For a typical Hyper-V host, expect about 2 GB to be necessary just to run Hyper-V and the management operating system. For a high memory host that will serve a high number of virtual machines, it is wise to plan for as much as 4 GB for the system and overhead.

Hyper-V’s management operating system uses a page file just like any other installation of Windows. However, its automatic process is likely to result in an inappropriate size. The next section discusses this issue.

Hyper-V and the Page File

In earlier versions of Hyper-V, the management operating system’s page file was automatically set by Windows to be at or above the same amount as system memory. Since a virtualization host typically has a great deal of memory, this was causing automatic creation of page files that were dozens or even hundreds of gigabytes in size. This is completely unnecessary for a Hyper-V host.

Unlike some other hypervisors, Hyper-V does not provide memory paging operations for its guests except under very rare, specific conditions. In those situations, it does not use the management operating system’s page file. Therefore, creating a large page file is wasteful as most memory contents on a Hyper-V system will never be paged to disk in any way that the management operating system or hypervisor will be involved with.

The default page file allocation system in 2012 and later is superior to earlier versions, but still often results in very large page file sizes. If the default allocation is not causing disk space starvation on your host, the recommendation is to leave it set to System Managed . Even though it’s not the most efficient use of space, it does allow the management operating system to respond to extenuating circumstances with less administrative intervention. Such situations are rare, so if reclaiming the space is of meaningful benefit, then do so.

Virtual Machine Memory

The bulk of the memory in your hosts will be assigned to the virtual machines. The bulk of a Hyper-V administrator’s resource management time is often focused on memory balancing. The best approach is to develop a habit of providing the minimal acceptable level of memory to each virtual machine and only increasing it after need has been demonstrated.

The simplest distribution method is to use static memory (sometimes called fixed memory ). This ensures maximum compatibility at the immediate expense of virtual machine density. It can also affect virtual machine mobility. In order to move a virtual machine from one host to another, the destination must have available capacity for that virtual machine; the less memory assigned to that virtual machine, the more likely it is to fit. Static memory is required for a number of server applications, such as Microsoft Exchange Server, as they allocate memory on the basis of what is available.

A more complicated method that leads to higher densities is Dynamic Memory . This technology operates by interacting with the memory manager inside guest operating systems to gauge what amount of memory the services and applications are requesting. If the requested amount exceeds the assigned amount, Dynamic Memory can assign more to that virtual machine (up to 1 terabyte or a lower administrator-defined limit). If other virtual machines increase their demand such that the total exceeds what is physically available, Dynamic Memory can determine if any guests have a lower demand than what is assigned to them and use a balloon driver to reclaim the excess for redistribution.

The following image illustrates a conceptual usage of Dynamic Memory for a single virtual machine:

what is assigned memory in hyper v

The amount of memory that the virtual machine believes it has starts at the Startup level. It can increase, but it can never decrease. Instead, the hypervisor calls on the balloon driver to expand its memory request to the guest’s memory manager. The guest believes that it has some control over the memory consumed by the balloon driver but that a local process is using it; in truth, it is controlled by the hypervisor; it might be assigned to a virtual machine or left in the host’s pool. What the diagram doesn’t show is that the balloon driver is only activated when there is memory contention. If a virtual machine’s demand is reduced and no other virtual machine requires an increase, Dynamic Memory does not activate.

There are several things about Dynamic Memory to take note of:

We’ve covered Dynamic Memory across several posts on our blog. You can find them here if you’d like to dive deeper into the subject:

NUMA in Hyper-V

NUMA (non-uniform memory access) is a technology used to maintain maximum performance in multi-processor environments. If your system has only a single physical processor, NUMA is not a concern. In multi-processor systems, only a very few applications are sensitive enough to memory performance issues that NUMA is something to worry about.

The contrast to NUMA is the older SMP design (symmetric multi-processing). In much older systems, the memory controller was a component that resided on the motherboard. Its purpose is to broker all connections to memory and to keep the contents of memory in a consistent state. When a CPU needed to access memory, a request would be sent to the memory controller. In multi-processor systems, all requests would be handled through the same controller. It would handle each request in a round-robin fashion which lead to an even distribution of process memory across available memory banks, hence the “symmetric” nomenclature.

Over time, memory controllers became integrated onto the CPU to address various performance and reliability issues. In modern multi-socket systems, physical memory banks are assigned to particular sockets. If that socket has a CPU, then those banks are handled by its memory controller. If a thread running on a different physical CPU needs to access memory, then it must go through the CPU that contains the owning memory controller. If the host is in SMP mode (called node interleaving on some systems), then threads will be evenly distributed across the memory banks by working through controllers on other CPUs.

If NUMA is enabled (which means that node interleaving is disabled on systems using that name), then the system tries to ensure that threads running on any given physical processor are assigned memory owned by that processor’s memory controller. This improves performance for applications that do not allocate memory amounts greater than the maximum size of a NUMA node. It should be reiterated that the performance difference is very small and very few services or applications are sensitive enough to the difference for it to be of concern.

Hyper-V does have the ability to project NUMA topology into virtual machines that are using fixed memory allocation. Use the memory settings in Hyper-V Manager or PowerShell to control it. The projected topology does not need to match that of the host. Do not change these settings unless you have a very clear understanding of NUMA and its effects. It is much easier to hinder performance than to improve it. As mentioned in the previous section, NUMA is not projected into guests configured for Dynamic Memory as guest NUMA cannot be changed on the fly.

Working with Memory

The easiest way to work with memory for a single Hyper-V guest is to use Hyper-V Manager as shown in the earlier article on Virtual Machine settings . The PowerShell cmdlet to modify memory for a virtual machine is Set-VMMemory. Its documentation can be found here . Host NUMA must be enabled in the system BIOS. Once enabled, there is nothing else to configure at the host level. You can view its status using PowerShell. The related cmdlets are Get-VMHostNumaNode and Get-VMHostNumaNodeStatus .

Now that you’ve gained an understanding of the challenges around memory and how Hyper-V handles it, you have the foundational knowledge to properly plan memory capacity for your deployment.

what is assigned memory in hyper v

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How to Configure VM Memory

How to Configure VM Memory picture: A

How much memory do I need to give this virtual machine (VM), and how do I do that? That very question has kept even the best IT pros up at night. But it's time we change that. We need to band together and attack our IT anxieties head-on. 

Today we are going to help you learn how to configure VM memory , how much memory you need to give to VMs, and how not to create memory performance issues in Hyper-V. 

An Overview of How to Configure VM Memory

Understanding how to assign memory to a virtual machine is an essential skill for sysadmins who want to make their hardware more effective and efficient. In this video, James Conrad shows you how to configure and allocate memory for a virtual machine — and why it's essential to allocate the appropriate amount of memory for your applications.

How do I Configure VM memory?

Configuring virtual memory allocation in Hyper-V is an easy process. So, without further fanfare, let's get into it. 

First, launch the Hyper-V Manager in Windows.  The Hyper-V Manager is the primary administration snap-in component for the Windows OS. Note that these instructions are for Windows 10 Pro, Windows 11 Pro, and recent versions of Windows Server with a user interface. Bare versions, or the base version of Hyper-V, do not include any user interfaces and must be configured via the command line.  In that case, the Hyper-V Manager can be used from another Windows machine to manage Hyper-V remotely instead, but that is an IT tragedy for a different story. 

After opening Hyper-V Manager, select your VM cluster from the side panel.

Next, locate the VM that you need to edit. Depending on your environment, you may have lots of virtual machines. If this is a home lab, there's a good chance you only have a few VMs on hand. 

After finding the virtual machine in question, right-click the VM and choose settings. This will launch the settings panel that has various settings for Hyper-V VMs. The settings that are accessible from this panel are only standard settings.  There are a ton more options available if you configure Hyper-V through PowerShell . 

In the settings pane, choose Memory. Pay attention to the first setting in the memory tab. This is where you set the target amount of RAM assigned to your VM. Adjust this setting and click Apply.

Adjusting the memory assigned to a VM in Hyper-V is as simple as that. We're not done, however. Nothing in IT is ever that easy, is it?

What is Dynamic Memory in Hyper-V?

Most hypervisors have something called dynamic memory, including Hyper-V. So, here's where life gets tricky. If you look under the Dynamic Memory area of the Hyper-V settings window, you'll notice a minimum and maximum setting. Hyper-V can adjust the amount of memory a VM uses in real-time. But, of course, things get muddy here.

The first setting you changed assigned the amount of memory a VM uses on startup. This is akin to a cold start on your computer. If you assign a VM 8Gb of memory, your VM will claim and use 8Gb of memory on startup. If you adjust the min and max memory settings to 8Gb, your VM will constantly claim and use exactly only 8Gb of physical memory.

That's not the wisest idea, however. Windows will use unused memory as cache space, but we don't need that in the VM world.  We want to utilize our hardware to its fullest extent. Using unused memory for application cache is typically at the bottom of our list. 

So, we'll set the min and max memory more appropriately. For instance, our minimum amount of memory might be set to 2Gb. A typical office-use PC typically doesn't drop below 2Gb of memory usage. We might also set the max memory to 16Gb. We don't want our end-users to keep opening apps and use all the physical memory a server is sharing between multiple VMs. 

What is Memory Buffer in Hyper-V?

Next, there is an option for a memory buffer. Since Hyper-V needs to adjust the memory allocated and used by each VM constantly, sometimes it's good to give a specific VM a bit of buffer space. 

For instance, if this VM is a mission-critical VM, you might want to give it a 30% buffer.  That means the hypervisor will assign 8Gb of memory to the VM plus 30% just in case it needs it.  That way, other greedy VMs don't come and take that valuable RAM space from our mission-critical virtual machine. 

What is Memory Weight in Hyper-V?

Finally, we have a setting for weight. This setting states where this VM falls in the pecking order. If the VM is super important, it gets a higher weight. That way, the hypervisor knows whom to service first. VMs with a lower weight are considered second-class citizens and only get resources after VMs with a higher weight are taken care of first. 

Wrapping Up

Assigning the correct amount of memory to your virtual machines is very important. The entire point of virtualization is to utilize more hardware while reducing TCO in the enterprise space. Virtualization is also a valuable tool for home labs. Nonetheless, if you assign too much memory to each VM, you will not be able to utilize your server hardware as best as possible. If you give too little memory to your VMs, you will have performance issues.  Either way, you are going to have a bad time. 

So, learn how to implement Hyper-V the right way. Hyper-V is a fantastic tool that also happens to be free. It's included with Pro versions of Windows, Server versions of Windows, and as a standalone bare-metal hypervisor. 

After you learn how to get those VMs up and running, learn how to use PowerShell with Hyper-V and become a virtualization god/ess. You can do amazing things with Powershell and Hyper-V, including automating your entire VM environment and enabling sunset settings like RemoteFX (something that must be done through the command line). 

Finally, learn how to cluster and replicate VMs in Hyper-V. All enterprise environments want both high availability as well as redundant systems. 

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Hyper-V Dynamic Memory: Startup memory vs Minimum Memory

When I setup a VM, I can set Min RAM, Max RAM, and Startup RAM.  I know what they each mean but not how they interact with each other.

If I have a VM that needs a lot of memory when it boots up because it has to start up a bunch of services and processes, but then it doesn't need as much once it's running under normal conditions, I can set the Startup RAM to be higher than the Minimum RAM.

E.g.  Startup 8 Gigs, Minimum 2 Gigs, Maximum 16 Gigs.

At boot, the VM gets 8 Gigs of RAM.  Once it's done starting up it could drop to as low as 2 or increase to as much as 16 depending on the demand of the VM.

The main question I have is, how long does Startup RAM remain active before it starts the Dynamic usage.

User: Mike B

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Author saurabh srivastava

Start Up RAM will be active until the VM boots up ,once server boots up , it will use Minimum RAM. Depending on the usage, VM will start consuming RAM to the value of MAX RAM (if demand is there)

If more RAM is required after the MAX RAM is reached, memory buffer comes into picure.

Just read the below artice and all your questions will be answered. :)

Author Mike B

I get that.  But what defines when the VM has "booted up"?  Is it a time?  (e.g. startup memory is active for 2 minutes)  Is it when a certain service or process starts?  That's what we're trying to figure out.

If I have a plain VM with Server 2016 and nothing else installed, if I set Startup RAM to 16 Gigs and Minimum to 2 Gigs, when I turn it on, it gets 16.  At what point will it stop using the Startup value and switch to the Min/Max values?

Author Alex Wittig

Kelemvor wrote: What defines when the VM has "booted up"?  Is it a time?  (e.g. startup memory is active for 2 minutes)  Is it when a certain service or process starts?

Without being 100%, I guess it's up to the hypervisor (hyper-v) to determine if the host really needs the ram and is 'successfully and completely booted.

The startup RAM is the amount of physical RAM that will be allocated to the virtual machines at startup. Regardless of what the actual RAM demand is, the host will reserve this for the virtual machine. From the virtual machine’s perspective, the amount of visible RAM will never drop below the Startup RAM amount.

Once the VM boot is complete and the hypervisor started , it will try to use the amount of RAM configured as the minimum RAM. How long that takes for this process depends and as said, seems to be determined by the hypervisor ( e.g. by guest / integration services that run on the VM and provide the hypervisor with feedback)

https://www.veeam.com/blog/hyper-v-dynamic-memory-managing-vm-ram.html Opens a new window   

Author Adrian Yong

Kelemvor wrote: I get that.  But what defines when the VM has "booted up"?  Is it a time?  (e.g. startup memory is active for 2 minutes)  Is it when a certain service or process starts?  That's what we're trying to figure out. If I have a plain VM with Server 2016 and nothing else installed, if I set Startup RAM to 16 Gigs and Minimum to 2 Gigs, when I turn it on, it gets 16.  At what point will it stop using the Startup value and switch to the Min/Max values?

When a server starts up, it will not really start up that many applications or "heavy" services. Even if it does, there is the paging to assist with RAM operations especially when your are talking about 2GB RAM vs 16GB RAM....

The main question is where do you see the RAM spike to 16GB or max and how long does it lasts ?

This topic has been locked by an administrator and is no longer open for commenting.

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Hyper-V Dynamic Memory Pros and Cons | Best Practice

When using virtual machines, memory is easy to be consumed fast. How to reduce memory consumption? In Hyper-V, enabling Dynamic Memory is an efficient solution to reclaim the unused memory to the required virtual machines automatically.

what is assigned memory in hyper v

Why do you need Hyper-V Dynamic Memory

Hyper-V Dynamic Memory was originally introduced in Windows Server 2008 R2 with SP1. It is designed to automatically balance the amount of physical memory occupied by virtual machines running on a server, improving the reliability of restart operations. Administrators can automatically adjust the amount of physical memory for virtual machines based on the application priority, thus optimizing application performance and memory space.

In older versions of Hyper-V, you could only specify a fixed size of physical memory for virtual machines. But virtual machine requires more memory at startup than its steady state, so two scenarios often occurred. One is that the allocated memory is exhausted and the virtual machine needs to be shut down and resized. The other is that the virtual machine is allocated too much memory than it actually needs, which cannot be reclaimed after booting, resulting in wasted resources. 

Now let's discuss Hyper-V Dynamic Memory pros and cons further.

Hyper-V Dynamic Memory

Hyper-V Dynamic Memory advantages and disadvantages

Hyper-V Dynamic Memory offers various advantages and disadvantages. If you want to know if it is suitable for you, please read this section carefully.

Advantages of Hyper-V Dynamic Memory

1. Improves the reliability of start-up operations. In Windows Server 2012, Smart Paging was introduced to ensure the reliable virtual machine restart operations.

2. Improve resource utilization. Dynamic memory makes full use of memory resources by automatically reclaiming free or low-load VM memory and allocating it to Hyper-V VMs that requires more memory.

3. Reduce hardware spending. Allocating memory to each virtual machine accurately reduces the waste of resources on hardware, thus saving costs.

Disadvantages of Hyper-V Dynamic Memory

Hyper-V Dynamic Memory also has drawbacks that can negatively impact VM memory performance.

Note : Database applications may have problems when Hyper-V Dynamic Memory is enabled. It is recommended that you use the applications that are compatible with Hyper-V Dynamic Memory to avoid any performance issues

1. When Hyper-V Dynamic Memory is enabled, issues with database applications may occur. It is recommended that you use applications that are compatible with Hyper-V Dynamic Memory to avoid any performance issues.

2. When the VM is running or paused, you cannot resize the maximum and the minimum memory amount as well as modify the VM startup memory amount.

3. Risk of overprovisioning computer physical memory in case you don’t keep track of memory allocation within your virtual environment.

advantages and disadvantages of Hyper-V dynamic memory

Best practice to use Dynamic Memory in Hyper-V

After learning Hyper-V Dynamic Memory pros and cons, you may have made your own decision. Hyper-V Dynamic Memory was integrated into Windows Server 2008 R2 Service Pack 1. If you want to use Hyper-V Dynamic Memory to improve virtual machine memory performance, please refer to the following practice.

Enable Hyper-V Integration Services

In order to use Hyper-V Dynamic Memory correctly, you need to first enable Hyper-V Integration Services . Since the release of Windows Server 2016, you can install and update Hyper-V integration services via Windows Update. Hyper-V integration service must be enabled in the host and guests. The steps are as follows.

1. Open Hyper-V Manager, then click Action >> Insert Integration Services Setup Disk .

2. In guest virtual machine, select the DVD drive with the installation files. Right-click the DVD drive and select Install Hyper-V Integration Services .

3. The installation/upgrade of Hyper-V Integration Services will begin. Reboot your client/server.

4. Access to Hyper-V Manager Summary to check the version of Hyper-V Integration Services.

Configure Hyper-V Dynamic Memory

Power-off your virtual machine before enabling Hyper-V Dynamic Memory.

1. Open Hyper-V Manager, select the virtual machine you want to configure. Then click Settings .

2. In the opened wizard, select Memory . You will see the multiple components such as RAM, Minimum RAM, Minimum RAM, Memory Buffer and Memory Weight. Let’s clear these components first, and configure them as you need.

configure Hyper-V dynamic memory

Startup RAM : It is the minimum amount of physical memory that the VM can use at startup. It’s recommended to set up Strat RAM high enough to ensure the VM starts quickly.

Note : When installing or upgrading a virtual machine's operating system, ensure that the Startup-RAM value meets the minimum memory requirements of the operating system.

start RAM

Minimum RAM : It’s the minimum amount of physical memory that should be assigned to the VM after it has started. You can reclaim the free and unused memory to the required VM until the minimum RAM value is reached (32 MB). When the virtual machine is running or paused, it’s impossible to increase the minimum memory, but you can decrease it.

Maximum RAM : It’s the maximum amount of physical memory that the VM can use. The range of Minimum RAM is from the assigned Startup RAM to 1 TB (1,048,576 MB). When the virtual machine is running or paused, it’s impossible to decrease the minimum memory, but you can increase it.

minimum and maximum RAM

Memory Buffer : It is a portion of physical memory which is set aside for the VM based on its memory needs. By default, the memory buffer value amounts to 20% but it can be set up to be as low as 5% and as high as 2000%. You can change the memory buffer value at any point, even while the VM is running.

There is a formula to calculate the memory buffer.

Amount of memory buffer = how much memory the virtual machine actually needs / (memory buffer value / 100).

memory buffer

Memory Weight : It determines the priority of the selected VM compared to other VMs on this host. In a production environment, some virtual machines have heavy workloads than others, so these virtual machines requiring higher performance should have a higher priority of additional memory than other general virtual machines.

memory weight

One of the disadvantages of Hyper-V Dynamic Memory is that you need to monitor the memory usage constantly, otherwise it will overprovision RAM and completely run out of memory. You can use native monitoring tools or third-party software. For example, you can check the VM memory state through the host in Hyper-V Manager or the guest VM in Task Manager.

In addition, facing a large amount of enterprise data that needs to be backed up, try to choose a proper backup method that saves storage space. For example, flexible backup solution and automatic clean-up plan can effectively reduce the need for storage devices, thus reducing costs and time.

Memory saving way to backup Hyper-V virtual machine

AOMEI Cyber Backup is a professional backup software for virtual machines. It offers resilient backup strategies that can flexibly track the Hyper-V changed data. It allows you to schedule the backup and set up a cleanup policy  to automatically delete unwanted backups. More benefits are as following.

Easy-to-use : Add all the VMs to the central console for backup and manage agentlessly. You can complete any operation via simple clicks. Flexible backups : Easily backup entire virtual machine with full backup and offers incremental and differential backups for changed data. Automate VM backup : Schedule tasks to backup unlimited virtual machines automatically and protect virtual machine continuously even though the VM is running. Fast recovery : Instantly recover the whole VM to its precious state or restore it to another host without any complicated configuration and reinstallation.

*You can choose to install this VM backup software on either Windows or Linux system.

1. Click Backup Task >> Create New Task to start scheduling automatic backups (for example VMware ESXi Backup ).

create Hyper-V VM backup

2. Select virtual machines and the destination to store the backups such as network or local location. For example, enter a NAS address and verify the identification to backup VMs to NAS .

backup Hyper-V to NAS

3. On Schedule window, for example, select full backup and incremental backup method, then set the backup frequency as weekly.

schedule Hyper-V backup

4. On Backup Cleanup window, specify the retention policy for each backup and choose to always retain the First full backup.

backup cleanup plan

5. Click Start Backup .

start Hyper-V backup

We have discussed the Hyper-V Dynamic Memory pros and cons in this article. To put it simply, using dynamic memory correct can reduce memory consumption and costs, but it also has the cons of memory performance. Please make choice according to your own needs.

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  1. Full Overview of Hyper-V Dynamic Memory Best Practices

    This Hyper-V Dynamic Memory value defines the minimum amount of physical memory a selected VM can use during its startup. Startup RAM should be

  2. Hyper-V Dynamic Memory Overview

    To provide a reliable restart experience for the virtual machines configured with less minimum memory than startup memory, Hyper-V uses Smart

  3. Configure at least the required amount of memory for a virtual

    Increase memory using Hyper-V Manager · Open Hyper-V Manager. · From the list of virtual machines, right-click the one you want, then click

  4. Managing VM RAM better with Hyper-V dynamic memory

    Keep in mind that to enable or disable dynamic memory, the VM must be powered off at the moment. So once you create a VM or edit an existing one

  5. Understanding Hyper-V Dynamic Memory (Dynamic RAM)

    This is the amount of physical RAM that will be allocated to the virtual machines at startup. Regardless of what the actual RAM demand is, the

  6. Memory Management, Requirements and Usage in Hyper-V

    Hyper-V itself needs about 300 megabytes of memory for its own process. For each virtual machine, any memory amount up to the first megabyte requires 32

  7. Hyper-V Dynamic Memory Configuration with Best Practices

    With dynamic memory, the Hyper-V host monitors the memory usage of the guest operating system and then can dynamically adjust the memory

  8. How to Configure VM Memory

    Most hypervisors have something called dynamic memory, including Hyper-V. So, here's where life gets tricky. If you look under the Dynamic

  9. Hyper-V Dynamic Memory: Startup memory vs Minimum Memory

    The startup RAM is the amount of physical RAM that will be allocated to the virtual machines at startup. Regardless of what the actual RAM

  10. Hyper-V Dynamic Memory Pros and Cons

    Hyper-V Dynamic Memory was originally introduced in Windows Server 2008 R2 with SP1. It is designed to automatically balance the amount of