Scenario

I have a 3 Windows 2012 R2 Hyper-V hosts which is participating in a cluster, all of the virtual machines are hosted on CSV's. We also use Dynamic Memory for most of the servers

We do regular reboots every week for our virtual machines, but we've found that sometimes, a virtual guest will suddenly stop requesting additional memory.  At the time of writing, I have identified 10 machines - on different hosts, and even different clusters which are exhibiting this behaviour.  They're also running OS's ranging from Windows 7 to Windows 2008 R2 and Windows 2012.

I have selected one to demonstrate below.

Here, you can see the virtual machine is configured to use Dynamic Memory

and here, you can see that it's not actually demanding more than the start memory, despite the fact that I've overloaded the servers virtual memory by using MSPAINT.

Workaround

Rebooting the virtual machine does not resolve the issue, but live migrating the virtual machine from the host it is on to another host suddenly allows it to demand more memory.  One can then live-migrate it back to the original host and the problem is no longer there.

Troubleshooting

We have performed the following troubleshooting steps:

• Verified that the Integration Services are up-to-date (currently running 6.3.9600.16384)
• Verified that the virtual server has up-to-date Windows Updates
• Checked the Hyper-V-Worker\Admin event log on the current host - no errors pertaining to this VM.
• Verified that the Hyper-V host has sufficient RAM (currently only using 542 out of 768 GB)
• Checked the System event log on the virtual machine - nothing out of the ordinary to report.
• Verified that all services which start with the word "Hyper-V" on the guest machine is running.

Using the following command, I can easily identify which machines are affected (this command applies to SCVMM only):

Get-SCVirtualMachine | where {$_.DynamicMemoryEnabled -eq $true -and $_.DynamicMemoryDemandMB -eq $_.Memory} | ft Name,HostName,OperatingSystem,Memory,DynamicMemoryDemandMB,DynamicMemoryMinimumMB,DynamicMemoryMaximumMB

I do not know any diagnostic program which can give me more information regarding the memory status of a server - specifically one which can tell me more information about Memory demand, and why it's not working. 

Considering that the problem is resolved when I live migrate the affected machine, it would suggest that the issue is with the host, but as live migrating it back no longer exhibits the issue - that seems to negate that theory.  Additionally, the other 103 virtual machines which run on this host seem to not show this issue.

It's almost as if the machine is being ran with static memory, and Hyper-V doesn't realise it's dynamic, but the moment it's live migrated, it suddenly realises this and enables dynamic memory.

Any thoughts?

We are in the process off moving our 2008R2 VM's from the 2008R2 HyperV servers to new Server 2012R2 Hosts.

We shut down the VM's copy the files and VHD's to the new CSV's en import the VM in the Hyperv Manager. Then we make them high available in the Failover Cluster Manager (Configure role - Virtual machine). We mount the integration tools and update the VM to version 6.3.9600.16384

For a specific type of VM (mostly RDS Host servers) we always had Dynamic Memory configured (when they were hosted on de 2008R2 platform), so we are using the same settings on the 2012r2 platform. The memory settings were;

Startup memory: 1024 MB

Minimum memory: 1024 MB

Maximum memory: 12288 MB

These VM's reboot every morning, this is done for specific reasons. But now once in a while (once per week/2 weeks) we notice that the VM's are not using more memory then 1024 MB while the demand is much higher. Rebooting the server helps most of the times, live migrating to another host also helps. In the VM we see that memory usage in the taskmanager is 99-100%, and after the move it immediately starts using more than the minimum configured amount.

Until the failover the memory usage was 1024 MB and it did not get any higher.

This happened several times. Last week we changed the Memory configuration to:

Startup memory : 2048 MB

Minimum memory: 2048 MB

Maximum memory: 12288 MB

But this morning we had a call about the performance of one of the VM's, We saw that it was only using 2 GB memory while the demand was much higher. After live migrating it to another host it started using more memory immediately.

The 2012R2 hosts are not overcommited, there is a lot of memory still available for the VM's. Those VM's never had this problem on the 2008R2 Hyperv platform.

Any idea why this happens?

Peter Camps

Hello,

We are using Hyper-V server and all .vhdx files are placed on a good SSD raid storage. ( on D:\ )

However, there is one folder that keeps some... temp VM files:

C:\ProgramData\Microsoft\Windows\Hyper-V\Virtual Machines

Can someone tell me how important is that these files to be in fast storage and is it related to the VM speed somehow?

Best,

Simeon

I'm putting together a server the hypervisor will be on a raid 1 on separate drives, if I were to use 5400RPM drives for this would it affect the performance even though the datastores will be situated on 15K raid 10 600GB drives.

Thanks

nambi

Hi guys,Really need your help on this one.

I have a customer that uses Hyper-V on Windows Server 2012 RTM.

The earlier IT guy (who was fired today) have been running the whole setup on dynamic disks.

One of the disks have 3,5 TB of data, and is therefore a VHDX file.
Today because of the heat the RAID controller reset, and that sadly corrupted the VHDX file.
Almost all of the VM's are dead, but this VHDX file holds ALL of the company data - such as dokuments, pictures, contracts, profiles, homedirs, and so on (you probably get the picture).
To top it all, the (now fired) IT guy didn't really check on the backup jobs - so no backup at all.

This company really needs help. I tried Bing'ing and Googling everything but no help as it is a VHDX and not a VHD file.

Whenever I try to start the machine, all I get is "Attachment 'D:\VHDs\FILESERVER1.vhdx' failed to open because of error: 'The file or directory is corrupted and unreadable.'."

I tried attaching it in disk manager with no luck (it will not open). I read that extending the size with VHDResize could uncorrupt the drive could help (but sadly it does not support VHDX format).

I really need your help here. Please join in with every crazy idea available.. These guys really need help.

The guy that comes up with a solution will not only recieve the credit, but I personally promise you an ice cold beer if you ever get to Denmark..

Or if you live in a country that I will ever visit, I will buy you one in your town.

THANK YOU SO MUCH!!

Microsoft: MCP, MCTS, MCITP: SA, MCITP: EA || CIW: Associate, Security Professional || CompTIA: A+, Server+, Linux+ || Citrix: CCA on XenApp || HP: ASP, ASP:SMB || Astaro: ACA, ACE

I'm new to VM's.  I grabbed the book and followed the directions, I don't see why every VM I've tried to set up stutters so badly.  I've gone through process monitors and I don't see anything that is anything close to a bottleneck.  VM is set up on it's own SSD, and it's host is a quad core xeon 2.5Ghz with 32Gb memory.   The original system I want to virtualize is an 8 year old atom 1.6Ghz with 2Gb memory, but at this point the VM can't keep up vs the bare metal atom and I'm still stuck running it.

Are these things supposed to just go dead for about a third of the time they are running?  Is that just normal?  How does anyone use them for any kind of I/O application like a network gateway or is that just not a use case for a VM?  Is there some registry thing I have to flick to tell it to run a specific VM in realtime, and that a 300ms latency every second is unacceptable? 

Hi all

We have Hyper v 2012 r2 Failover Cluster running . When we copy some Gbs file from lets say Host 1 to Virtual Machines resides on Host1 .

Copy starts and network speed down to 0 kbps . VMQ is disable on Physical Network of Hyper V switch.

Please advise.  Below is the output of Checksum Offloading.

Name                           IpIPv4Enabled   TcpIPv4Enabled  TcpIPv6Enabled  UdpIPv4Enabled  UdpIPv6Enabled
----                           -------------   --------------  --------------  --------------  --------------
NIC                           Disabled        RxTxEnabled     RxTxEnabled     RxTxEnabled     RxTxEnabled

Should we disable Checksum Offloading or it is okay ?

Regards

Hi there,

I am trying to increase the display resolution to 1600x1050 for my virual server (Hyper-v), but the max I can get is 1280x1024.

I installed the Integration services and all the updates for the host os (win 2008 Enterprise) and guest os (win 2003 R2 Enterprise).

any idea?

Thanks,

LOA

See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
   at System.ComponentModel.ReflectPropertyDescriptor.SetValue(Object component, Object value)
   at System.Windows.Forms.RadioButton.PerformAutoUpdates(Boolean tabbedInto)
   at System.Windows.Forms.RadioButton.set_Checked(Boolean value)
   at System.Windows.Forms.RadioButton.OnClick(EventArgs e)
   at System.Windows.Forms.RadioButton.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
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mscorlib
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Microsoft.ManagementConsole
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System
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Microsoft.Virtualization.Client.Common
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Microsoft.Virtualization.Client
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************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.

For example:

<configuration>
    <system.windows.forms jitDebugging="true" />
</configuration>

When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.

Hi,

I did a clean install of the Windows 10 Insider Preview build 10130.

After that, I tried enabling Hyper-V features (via the enable Windows Features). It said it required a restart and upon restarting, it gave a message at the boot screen saying that it is unable to complete installing features and is reverting. This is followed by two restarts and then I am able to login.

Please help me. I need to enable Hyper-V to install the Windows 10 Mobile emulators.

Thanks,

Ratish

I just purchased a new powerful server and placed Windows Hyper-V Server (free version) on it (we do not have System Center).

We use already prebuilt images for student labs (consists of two servers that work together for an enterprise application).

One guest image has AD loaded with its own domain on the other is a client server. We have an automated system that copies the images and then imports then and fires them up.

The problem is they all have the same hostname and it even looks like they get duplicate ip addresses on the Private or Internal switch (only the external virtual switch receives dhcp, I am not sure how the other internal/private switches obtain their ip info). So if we place 3 students on the new server (6 VMs total [3 DCs and 3 clients]), The first two VMs appear fine but attempting to login to anyother DC results in the error: "The Local Security Authority cannot be contacted", I can only guess it getting confused on which is the real DC.

The host has 3 Internal Only switches and 1 External switch for internet access.

Is there a way to isolate each student's environment? I am guessing System Center can help but I am looking for other possible solutions.

Thank You, Joe

Im using Hyper-V on a Windows Server 2012 R2 host. I have two Hyper-V guests: One is a domain controller and another is for a program that needs (almost) all the power.

The host itself has 64GB of RAM, it has Hyper-Threading disabled (the program doesnt perform better with HT enabled, this has been checked out personally) and two processors Xeon E5 2650 v3 (which would mean there are a total of 20 REAL cores).

What is the best way to configure NUMA for the guest for best performance?

Hi,

It seems my Hyper-V 2008 R2 two nodes cluster has a communication problem since at least two days (I don't know when it started)

Virtual machines on one node have lost the ability to ping virtual machines on the other node.

Has anyone ever had this problem?

Thanks for your answer.

Hey all. I'm finishing up the design for a Symantec Enterprise Vault solution that is going to get migrated from physical hosts to a new Hyper-V implementation. (Complete app migration, not just a P2V.)

For those unfamiliar with the product, EV has two primary storage requirements; slow storage for the actual archived items, and fast storage for the indexes of that content.

The storage backend is going to be a NetApp SAN with two filers, one dedicated to SATA and one dedicated to SAS.  The Hyper-V VMs (3 of em) are going to run on a Hyper-V cluster, consisting of two same-rack physical servers.

The slow storage is easy, as it can just use a standard CIFS share.  The fast storage is what I'm concerned about.

My plan was to use two cluster-shared volumes (both would be FC LUNs from the SAS filer).  The first will hold the VHDs for the VM OS's.  The second will hold VHDs for the indexes. (3 VMs and 3 indexes, so each VM gets an OS VHD and an index VHD.) 

The only concern I have is with those index VHDs.  (Yes, by VHD I mean VHDX.)  They're going to start at about 4 TB each, and could grow as big as 7 TB.  That's a lot of data to be sitting in a single file, and I'm wondering if I'm overlooking an easier way to present those indexes to their corresponding VMs.

Thoughts?  Thanks!

I just setup one server 2012 r2 host and two server 2012 r2 guests. There was a storm that came through over the weekend and there was a power failure. I don't know how long but the server is on a backup. On Monday morning when I came to work, I noticed the first guest, an exchange server had a yellow caution on the nic in the tray. I rebooted the server and it cleared. Later in the day, I was working with a Dell tech preparing for a migration and I noticed the other guest, a WSUS server had the yellow caution on the nic in the tray as well and it was telling me it could not contact the default gateway. Rebooting has not helped with this guest. I've tried removing the nic and reinstalling it, but the same issue. I switched it to DHCP, but it cannot contact the dhcp server. I can ping the nic locally, but nothing else. What steps can I take to troubleshoot? Since this is a new install, could I get phone support from Microsoft, if we cannot resolve the issue here? Just not sure how to troubleshoot a virtual nic.

Additional info. This is a Broadcom extreme dual onboard nic. I saw an article about this issue and updating the driver. There was a qlogic driver update on the Dell site, so I downloaded and installed it. No change, so I rebooted. After the reboot, still no change. So, I look under device manager to make sure the driver was updated and I see to cautions:

under Hyper-v virtual switch extension adapter: 

This device is not working properly because Windows cannot load the drivers required for this device. (Code 31)

An object ID was not found in the file.

under Microsoft hyper-v network switch default miniport: 

This device is not working properly because Windows cannot load the drivers required for this device. (Code 31)

An object ID was not found in the file.

I have to correct something, yesterday, I rebooted the second guest server, exchange and the issue cleared, but in checking just now, both guests are displaying the yellow caution and reporting no connection to network. Is this as simple as removing the guest nic and re-installing?

Hi, here is my problem.

I've set up 3 hyper-v hosts windows 2012 R2 in a Cluster.  My problem arise when i try to backup my VM's with Veeam, i can take a crash consistent backup but when i try to use the "Application Aware Processing" it fails.  

Here is the error reported by Veeam :
Unable to create snapshot (Microsoft CSV Shadow Copy Provider) (mode: Veeam application-aware processing). Details: Writer 'Microsoft Hyper-V VSS Writer' is failed at 'VSS_WS_FAILED_AT_PREPARE_SNAPSHOT'. The writer experienced a transient error. If the backup process is retried, the error may not reoccur. --tr:Failed to verify writers state. --tr:Failed to perform pre-backup tasks.
Make sure VM does not have 'iSCSI Software Target Storage Provider' feature installed.
Retrying snapshot creation attempt (Writer 'Microsoft Hyper-V VSS Writer' is failed at 'VSS_WS_FAILED_AT_PREPARE_SNAPSHOT'. The writer experienced a transient error. If the backup process is retried, the error may not reoccur. --tr:Failed to verify writers state. --tr:Failed to perform pre-backup tasks.)
Unable to allocate processing resources. Error: Writer 'Microsoft Hyper-V VSS Writer' is failed at 'VSS_WS_FAILED_AT_PREPARE_SNAPSHOT'. The writer experienced a transient error. If the backup process is retried, the error may not reoccur. --tr:Failed to verify writers state. --tr:Failed to perform pre-backup tasks.

 I've reboot my hosts multiple time and retry the backup job multiple times to.I can see, when i use "diskshadow", that the VM's are excluded from backup because the volume is not in the shadow copy set:

I have no problem taking backups with Veeam from my Windows 2008 R2 Hyper-V Cluster

Can somebody help me figure out this issue ?

Thank you

I have extensive experience with VMware, but wanted to setup Hyper-V home lab and learn it. I have a desktop with 8-core AMD processor and 32GB RAM, with 400GB SSD, so I intent to install two Hyper-V VM inside VMware workstation, with 4vCPU, and 12GB, I will also have one Win2008 R2 (1vCPU, 4GB) as DC, and another windows 2012 R2 (to install System Center 2012, I have the CD key). I have dedicated NAS for shared storage. I have the following question.

1). Is System Center the Microsoft solution similar to VMware vCenter 5.5?  Can I do shared storage?  Live migration (My Hyper-V is free bare-bone installation), how about HA, FT?

2). VMware has the vSphere client, presumably Hyper-V manager (installed on windows 8.1 or Winserver 2012 R2) is Microsoft's answer to that, my understanding is even though I use bare-bone Hyper-V, my function is not limited in anyway compare to type-2 Hyper-V installed inside Windows 2012 server, am I right?

3). Microsoft obviously pus their new OS very hard, so using Hyper-V 2012 R2, can I use Windows XP, Windows server 2012 ?  I strongly suspect Microsoft would intentionally limit the scope to protect their OS business.

   thanks a lot for your answer.