Vm stun during snapshot Secondly it suggests: Dec 19, 2024 · When removing snapshots after backing up a virtual machine residing on an NFS datastore using a backup application, the virtual machine becomes unresponsive for approximately 30 seconds. forceSync = TRUE Cause: This message is reported if the virtual machine is powered on and the asynchronous consolidation fails after 10 iterations. Removing snapshots after backing up a virtual machine residing on an NFS datastore takes a long time to complete. See full list on virten. 5 Update 2 hosts freeze at the *creation* of a snapshot. Jan 8, 2020 · Hi . 6 to find out how long each VM is stopped at a snapshot (stun time). shut the VM down completely then snapshot it. Tested was default IO-tests and java application performance . This optimizes the consolidation process. VMware vSphere. 0, the consolidation and commit phases of any VM snapshot has always followed the same procedure: an additional helper snapshot was created to “freeze” not just the base virtual disk, but also the snapshot disk, and once the changes stored in the snapshot disk have been merged into the base disk, the helper snapshot was Jul 5, 2018 · Before vSphere 6. The first time the job runs it must run an Active Full backup. May 3, 2013 · As to using VMware snapshot technology question, then, indeed, you can observer the "usual" stun/unstun problem from VMware during VM snapshot commit operation. Each virtual machine's log file (vmware. Google vmware+snapshot+stun. Apr 16, 2025 · When removing snapshots after backing up a virtual machine residing on an NFS datastore using a backup application, the virtual machine becomes unresponsive for approximately 30 seconds. 6. Might help track down your issue. that usually takes 1 ping to update. It task status window in Vmware web client i see "Creating VM Snapshot 0%" and it hangs. When taking snapshots of VMs, the quiescing option provides additional control to ensure consistency of the VM’s data over and above the regular crash consistent snapshot - additional work is required to script or configure those controls and once in place these can be used by VMware Cloud DR when creating Recovery Points for Disaster It sounds like what you're seeing is extended VM Stun times when the VM finishes consolidating the snapshot. After the switch is successful the source disk will be deleted. Busy storage can also have an impact. After that, performance testing is done with 1, 2 and more snapshots. Nothing to do with Veeam. A Database has an extremely high transaction rate and will cause a snapshot to balloon in size very rapidly. They capture and retain the active state of a VM. Sep 21, 2022 · In both cases, the snapshot consolidation takes 12 or more minutes. This will ensure that the bind operation is held by the same ESXi host and snapshot consolidation completes without causing long pause. VMware have directed us to the following article referencing an issue with VM performance - Virtual machines running on VMware ESXi 5. Jun 9, 2016 · If you do not want to stun / pause the virtual machine you can set snapshot. The stun time might go high depending on different aspects. vmdk, this virtual machine is not using any of these files. In the case of VMware, if you run out of space in the LUN the VM will stun (pause) and will only un-stun if you free up space in the LUN which may be impossible. When the backup is completed, the snapshot is merged and virtual disks are consolidated, resulting in what is typically an imperceptible ‘stun’ where I/O is paused during the final disk consolidation operation. IMPROVeD SnaPShOT hanDlInG In VMWaRe vVOlS Because each VM has its own virtual volumes on the array, it is possible to utilize integrations between vSphere and the array to conduct array-based snapshots on a per-VM level. Consider the following before enabling or disabling the quiescing during the backup: Dec 11, 2014 · Looks like a similar issue that is described over here > Snapshot removal issues of a large VM That's a pretty large topic to read, so as a short summary - VM stun can happen during snapshot commit operation. Veeam is successful in resetting CBT but vSphere (because of the existing snapshot/s) is still running a process on the VM which basically stuns/locks it. log of the virtual machine which has the impact of high stun time, you may see similar error: Checkpoint_Unstun: vm stopped for 63104614 us (63. The VM gets stunned during a snapshot. In addition, there are configuration issues with ESX/ESXI VMs that can cause virtual machines to be unresponsive. Sep 26, 2013 · As in thread title pretty much. As far as I can tell, the procedure was probably devised back before VMware snapshots were fully application-aware. Mar 12, 2015 · VM's running on several ESXi 5. Causes. Any active or manual snapshot on VM before backup starts ? No. The freeze periode depends on the VM. This issue is exasperated on large datastores (32TB or greater). Usually under 1s. . However, it has been observed that when VMware attempts to remove the snapshot created during a Veeam job operation, and there was a snapshot present on the VM before the Veeam job, snapshot stun may occur. ) you might want to explore other backup options such as using an agent inside the guest OS instead. Jan 19, 2011 · Normally there is a performance impact during snapshot removal, which can vary significantly based on the load on the VM, especially I/O load, but the "pause" should usually only last a couple of seconds as the final "stun" freezes the system to remove the final snapshot. Jan 22, 2024 · Memory snapshots take much longer to create. This will cause your VMware snapshot to grow larger (especially on high change machines, like SQL or Exchange) and thus it has a higher chance of Snapshot Stun during the snapshot removal. i have not seen any ping drops during snapshots though, only vmotion Jan 17, 2023 · On a powered on VM with existing snapshots if you do an Active Full which resets CBT it causes the VM to stun. 3. Aug 24, 2021 · VMware has tested the performance impact of snapshots. Is VM doing any IO intensive operation during backup time ? Yes, this is precisly the moment where the vm stun 40s, when there is an "normal" IO rate the stun are like 1s. Also we have an existing topic discussing this issue, please check it out, should be useful. I understand that vSphere 6 has reduced snapshot consolidation times dramatically so that may be an option. Ensuring High Availability during Backup and Recovery Jun 12, 2013 · In the final post in the Backup section of our Accidental DBA series, I’m going to a look at backups using virtual machine (VM) snapshots, which are popular among VM administrators but may not be the right solution for your SQL Server recovery needs, depending on your RPO and RTO requirements. The duration of the stun will depend on the number of vmdks and speed of datastore metadata operations (e. Check the other virtual machines. LOG. May 24, 2021 · A virtual machine may also become unresponsive for a short period of time during a snapshot deletion. Jan 20, 2015 · Can we confirm if this VM freeze is not seen during snapshot creation? The consolidation of VM has point where it has to stun the VM in-order to complete the process of switching from Delta disk to base disk. During the snapshot, VMware will create a Delta VMDK file. 5, I can't recall) I was told that vSphere will only use 10 threads per operation and if there's a queue the VM is paused until that queue clears and the operation completes (maybe it uses more threads now, maybe the support person made Storage snapshots are absolutely nothing like VMware snapshots even if they have Netapp tools and vss integrations. Stuns of a few seconds, a couple times (presumably once per VM disk as they're consolidated) has triggered this behavior. Reverting a snapshot may result in unexpected behavior on your clients. This nearly eliminated the stun especially when we upgraded vcenter to 6. Not to say it can't happen, but so far I've had good experiences with VMware snapshots. The available storage capacity affects the stun time during snapshot creation. VM snapshot INCLUDING memory NOT Quiesc. When the snap is cleared the files are merged back into a single file and that process can cause a stun where the vm essentially pauses as it waits for the merge process to complete. VM Stun is what you want to google for other ideas. Maybe the timeout during the snapshot removal is the "usual" stun/unstun problem coming out from VMware itself? Luca. wrote:Yes, there is no difference in how VM snapshot is committed, so this shouldn't be the case. Get Enterprise and backup from storage snapshots. What is the maximum stun time for the VM during vmotion operation, snapshot creation/deletion? Is there any setting to verify this? Is there anyway to reduce the stun time of the VM? Unfortunately, right now vmware has closed my tickets with a response of basically, "Don't use snapshots on sql servers, veeam shouldn't be backing them up. Typically, it happens so quickly you don't even notice. During these four days, the VM was frozen while the snapshot was being deleted, and I couldn't do anything. Check for orphaned snapshots on the VM. Veeam uses May 15, 2025 · Note: Time involved to commit snapshots is environmental and subjective. A very intersting thread. During my research I found the vmware. During a backup, Commvault instructs VMware to take a VSS-enabled snapshot, which will in-turn tell the file system and any applications to write any in-memory change to disk with a temporary I/O pause. Make sure VM does not have any other snapshots (including hidden). The snapshot removal will stun the VM at least 2 times during this process. - Assuming the VM runs a version of Windows, the vCenter sends a request via the VMware Tools to perform a VSS operation inside the VM, this process being known as a quiesce. Oct 23, 2017 · Hi All, I’m running VMWare 6 with windows VMs and have noticed that when ever a snap shot is created there is a slight “pause” in the machine (about 4 pings worth). " This is 22 words. All the new nicold wrote:We've been working through some VMware related issues with the OS of VMs locking up and requiring a vMotion or suspend/resume to get things unstuck again. Apr 28, 2013 · Generally, disk performance (and size expansion of the VM's storage) is the concern with snapshots, as disk is now split between the flat disk and the snapshot disk (potentially multiple snapshot disks); a simple disk operation when there is no snapshot can significantly balloon, potentially needing to work with data on both the base and (multiple) snapshot disks (which are not contiguous with A couple of things to check with regards to Veeam are a) see if you can use Direct NFS mode (this can give you some good performance increases) and b) if you happen to be using a supported SAN, you can backup from a storage snapshot as opposed to a VM snapshot in vSphere. If you do face this situation, then here you go a couple of tips that might help: 1. Jan 19, 2010 · There are the log files created on the datastore next to each VM. VM snapshot NO MEMORY OR Quiesc drops ping during snapshot and removal of snapshot. We're currently experiencing minor stuns during both snapshot creation and removal, on all VMs. Whether those are tolerable depends on your individual scenario. Challenge During the snapshot creation or commit phase of a Veeam Backup or Replication job using vSphere, a primary node in a DAG cluster may lose the heartbeat long enough to cause a Snapshots shouldn't stun a VM for that long, this only happens if the data move rate is faster than the consolidation rate, which basically means your storage performance is undersized (also means your database is abnormally write-heavy likely). May 28, 2018 · I want to use vRealize Log Insight 4. The vmsync driver is only supported with vSphere 5. On a side note, I've found that additional vmdk drives increase stun times considerably. snapshot. Most seen among this is the time taken to switch from delta disk to base disk, Feb 20, 2025 · Virtual machine could also freeze when the I/O in the virtual machine is high and the quiescing operation is unable to flush all the data to disk, while further I/O is created. This pause, drops the network connection and causes the SQL Cluster to lose quorum and attempt to fail over. The only way is to reset the host. When you get the issue again, check the corresponding VM logs files - the stun times are labeled pretty clearly there. Avoid creating snapshots or backups for multiple virtual machines simultaneously. No heavy loads, so no long stuns - total stun periods are about 2-4 seconds per VM during backup, and the stun is not continious. I work with a similar setup quite regularly. I did not try with normal snapshots because there should be no difference without any integration Mar 25, 2013 · VSS is used to freeze I/O in a Windows compliant program to guarantee data consistency, but to my understanding VSS is not invoked during the commit of the snapshot itself. I typically see a ping or so drop on larger memory VM’s. Although unlikely, it is possible that another virtual machine is storing its snapshots in this directory. We’re using reverse incremental forever backups and the Veeam server is using direct SAN. Oct 11, 2022 · At some point the ESXi host will need to stun the VM and depending on those factors, such a stun can take multiple seconds. pings will fail, no IO). VM was rebooted 6. Besides the SQL Server we have some files there as well, this will be changed next week but still I am interested what a snapshot does to a running system. net Oct 4, 2012 · Veeam Backup & Replication can back up a VM that has snapshots present. As far as I understand VMWare let SQL Server freeze the DB and gives him an amount of time to clear the cache and complete running Jul 9, 2013 · As detailed in the Veeam Backup & Replication User Guide, a snapshot is created on a VM that is being processed by a Veeam job. Drops ping during snapshot and removal of snapshot. I do not know where it can come. To estimate the time it will take to remove snapshots, see Estimate the time required to consolidate virtual machine snapshots The consolidation/Removal task hanging at 99% is in most cases related to: Virtual Machine snapshot size on disk (Delta or sesparse file size). We have optimized the snapshot process reducing the stun time during snapshot creation and deletion. 5. Jul 17, 2015 · I had a similar problem and i solved with a VMware VM Parameter: snapshot. x or newer, the advice in this article should only be implemented if node failover issues occur due to snapshot-induced VM Guest OS I/O stun. This issue also occurs if attempting to to create a quiesced snapshot on a virtual machine that does not have free space on the underlying virtual machine hard disk. Memory snapshots are used to allow reversion to a running virtual machine state as it was when the snapshot was taken. The longer you wait, the bigger the snap gets. both vMo and SVMo are impacted by how much memory or disk changes occur during the transitions. Our VSS agent provides: Hands-free management – Once we detect a Windows VM, we auto-deploy our VSS agent via VMware tools. I would check the vmware. Jun 19, 2024 · The long VM stun time reported during snapshot create was due to the time taken to search for suitable Resource Clusters (RC) to affinitize allocations to . Effectively, this means taking an application snapshot (freezes IO), then taking a VM snapshot (which contains the application snapshot). At first I thought the system was BSOD'ing, but I have disabled "Automatic restart on blue screen" and the system doesn't halt at all -- it's almost like something is rebooting it. When you create a memory snapshot, the snapshot captures the state of the virtual machine’s memory and the virtual machine power settings. Dec 4, 2012 · It could also be due to overloaded primary storage and busy VM, which results in snapshot removal process unable to catch up with the new writes (there are certain snapshot size and storage performance thresholds before hypervisor will allow VM stun for that final aux snapshot commit, to ensure stun time remains acceptable). Jul 5, 2018 · Before vSphere 6. Understanding Types of VMWare Snapshots Memory State Snapshots. Jul 4, 2019 · SAP, also Orchestrator on some VM, or custom apps. After quiescing, a software snapshot of all virtual machines for the subclient is created using VMware tools. backups and eliminate the need to perform regular full-VM backups. The snapshot that needs consolidating is 2TB in size. The second thread also refers to disconnects of the VM during snapshot removal, a known issue caused by VM stun which is only temporary, but yet again is specific to VMware, not Veeam. log of affected VMs and search for the stun time. In many cases, we've had to set our disks to Independent Persistent so that the SQL servers don't snap the data volumes during our vRanger backup. VMware Support tells me that in ideal lab conditions that consolidation will take around 2. Workaround: The PowerProtect Data Manager VMware Protection solution offers the Transparent Snapshot Data Mover (TSDM) solution, which does not require a VM snapshot to perform the backup. Removing a large VM snapshot may cause a long stun time at the end of consolidation, depending on the snapshot size. Note: Beginning in ESXi 5. 0, the consolidation and commit phases of any VM snapshot has always followed the same procedure: an additional helper snapshot was created to “freeze” not just the base virtual disk, but also the snapshot disk, and once the changes stored in the snapshot disk have been merged into the base disk, the helper snapshot was Another cause of VM stun occurs when taking a hypervisor-level snapshot with virtual machine memory, which renders the VM inactive while the memory is written to disk. VMware recently patched an issue in 6. so for near real-time application, it can inflict loss of ongoing transactions and sessions. The incremental backup will be much shorter in comparison and thus the snapshot is smaller. To take a snapshot of a suspended virtual machine, wait until the suspend operation finishes before you take a snapshot. Feb 7, 2011 · What is typically causing the issue is VM stun during snapshot commit. 7U2 or later Aug 13, 2017 · At a guess yo're seeing VM stun either when creating the snapshot, or more likely when it's being consolidated after deletion. Creating Snapshots. When using thin VMDKs, there can be an increase in disk usage when consolidating snapshots and unmapping the deleted data. Jun 23, 2015 · Vitaliy S. Deleting Snapshots As mentioned above, it's called a VM stun. " Reply reply more replies More replies More replies More replies More replies More replies Snapshot consolidation on vVOL-based virtual machines causes the virtual machines to be stunned while the snapshot vVOL is being deleted. This has to do with the consolidation process. ) Hey @Vsicherman Getting Application Consistent snapshots is very important for the recoverability of files and application data on a VM. May 17, 2010 · You can see how long (in microseconds) the VM is 'stunned' in the vmware. This causes an issue since we have several RDP servers and SQL servers and when the snapshot occurs it will disconnect those servers. Snapshot History. Why is this? The reason the Virtual machine may become unresponsive is because of the stun process. Druva can back up a VM that has snapshots present. The process is the same for both Windows and Linux. In case of pending change block tracking initialization this phase of snapshot creation will result in longer stun time. For Windows guests, the Rubrik cluster uses the Rubrik Backup Service software to pass a request to the Volume Shadow copy Service component of the Windows OS. Some VMs even have a freeze period of 1 minute! Network connection is lost during freeze. The snapshot removal is taking longer on several virtual machines. This creation of this snapshot causes the VM's base disks to be in a read-only state during the job's read operation. and I attempted to delete one from another VM, which took four days to complete. Baseline performance is a VM without a snapshot. log file for the VM for a message similar to the Normally the stun operation is only during the final step of snapshot removal. log file in the directory where the . 7u3 that was causing stun times on our MSSQL VM to randomly be over 10sec. Drops ping During snapshot and removal of snapshot. I'm starting to have issues with my VEEAM backups. Nov 4, 2019 · We’ve been using VMware and Veeam for a while now and I’ve been coming across a problem where a VM will lose connection and effectively go offline during the backup. From a VMware KB: A snapshot removal can stop a virtual machine for long time. Jan 27, 2014 · The bottom section of VMware KB: A snapshot removal can stop a virtual machine for long time kind of describes the behavior, though I'm not talking about long stun times. Checking if virtual machine is running on a It depends. Once the removal completes, the virtual machine starts working properly again. The VMware snapshot is removed a lot quicker too. There is a massive difference between differencing disks and redirect on write snap shots. Oct 29, 2020 · We have optimized the SESparse snapshot process reducing bloat. If you want to minimize the impact of snapshot commit operation, then integration with storage snapshots will definitely help here. Oct 24, 2019 · For a highly transactional application like databases (in this case the Oracle DB), side effects can appear due to VM stun. ESXi. Rubrik leverages built-in VMware snapshot capabilities to capture point-in-time data from your vSphere environment. May 25, 2017 · As long as you can ensure VSS is being used to quiesce the VM and take the snapshot, there’s no reason to power down the VM as described. The process involved in the I/O is the VM-World process. vmx lives. May 2, 2025 · VMWare ESXiを導入するうえでの仮想マシンやハイパーバイザの概要について、記事にします。 仮想マシンを使用しない通常の物理サーバ構成では、基本的にCPU・メモリ、ディスクの物理リソースを1つのOSがすべて占有します。 Nov 14, 2014 · During that timespan we had a huge performance problem. The stun/freeze happens due to changes written back to the base disk from the Delta disks. 5 or 6 then get current and see if you still see the issue. BTW, the log file Gustav was talking about, to look for STUN times is VMWARE. There are also indications of stun times in the same vmware. If this is a high-I/O VM (busy SQL server, Exchange, etc. Snapshot Hunter . Deleting a snapshot may cause very poor performance while the changes are merged. create new delta disks, etc. Dec 17, 2015 · The snapshot should be transparent/not visible when not using VSS or VMware tools. Ours does a snapshot then the San takes a snapshot and then veeam backs up off the san snapshot. x, the virtual machine snapshot delete operation combines the consolidation of the data and the deletion of the file. It then goes on to describe the risks and downsides of this approach. Taking and removing snapshots can, in VMware terms, "stun" a server if there's a lot of I/O occurring during the operation. This happens Aug 6, 2021 · Based on documentation, it seems that the snapshot functionnality introduces : - a short virtual machine freeze state called "Stun" time, which pauses the execution of the VM at a machine instruction level for up to 1 second. In vmware. There’s no manual install and un-install. To determine this stun time, check the vmware. During this close/delta create/attach period, the virtual machine is stunned. You can use Rubrik Security Cloud to provision a Rubrik Cloud Cluster Elastic Storage on AWS or a Rubrik Cloud Cluster Elastic Storage on Azure. 0以後は起こりにくくはなっていると聞いたことがありますが、最新のESXiバージョンでも発生することはあるのでしょうか？ Jan 17, 2014 · Other than this, the issue is all on VMware, the stun process is really something we can't prevent to happen because Veeam simply instruct vCenter 8and then the ESXi running the VM at that point in time) to consolidate the snapshot. N/work loss can take seconds during the consolidation with large snapshots (though I've seen minutes in some cases). Taking snapshots stuns the VM. To level set, application stun goes hand-in-hand with any snapshot operation. To create a VM snapshot, the VM is “stunned” in order to (i) serialize device state to disk, and (ii) close the current running disk and create a snapshot point. From the commvault side the backup is completing. log in the home directory of each VM, in it the time under "Checkpoint_Unstun: vm stopped for 6763 us" is logged e. Note that snapshot commit in VMware may take multiple stuns, so read the full log around that time. The affected VM protection mechanism stun is by design during the VM Snapshot creation. May 30, 2013 · Good Morning All, Thanks for taking the time to look! I have an issue with numerous virtual servers on our server estate. Test Results: Impact on vVOL depends on the storage system, because The VM will switch from using the source to the target disk, when the source and target disks are equal. 0 (maybe 5. The timing of these correlates roughly with the timing of the unexpected PC reboot. Answer. Jun 19, 2018 · When a backup is performed using HotAdd mode for VMs residing on NFS storage, target VMs become unresponsive for 30 seconds and removing snapshots takes a long time. It actually happens every time a snapshot operation is performed. If none of them refer to these files, they can be safely erased. because i know stopping the deletion process could potentially destroy Jan 8, 2020 · Hi . I have had it stun/freeze the VM while trying to consolidate, but it has always come back when I leave it alone. Mar 27, 2013 · When using vSphre 6. Very active vms, active as far as storage IOPs, when a snap shot is taken the new change bits go into a different file. In fact, after i take a snapshot the time offset become about 1 minutes. Nov 22, 2019 · To resolve this issue place the virtual machine which exists in the vVOL datastore and the virtual machine which involves in the backup process on the same ESXi host. Mind you, I think there’s still a risk that the VM snapshot will put the OS in an inconsistent state, despite the application itself being in a consistent state. What version of VMWare are you running? ESXi 6 had significant improvements in VM stun around snapshots. log) will contain messages similar to: Apr 1, 2025 · The vmsync driver ensures that the file system is in a consistent state prior to the VMware snapshot being created. As recently as ESXi 6. Storage performance influences the stun time. Sep 27, 2019 · @Gostev - thank you for the quick response!! Maybe without understanding exactly how it all works, I'm trying to understand if there is a way to do a backup of a vm, from the storage snapshot, to that independent copy on a backup repo without having to stun the vm with a vmware snapshot. Also to rule out Veeam, try to manually create a snapshot, leave it active for the same time the backup job takes and then delete it. g. Failover occurred between the primary and secondary nodes during the snapshot removal of the VM hosting the primary nodes. Memory state snapshots are the default option for taking snapshots in VMware vSphere. the only way to recover the VM is a hard stop and start. Veeam called VMWare to remove snapshot per normal – successful 5. Tests included: vVOL, VMFS and vSAN. An additional iteration is performed if the estimated stun time is over 12 seconds. 2. The NTP in the server is configured with the domain controler NT5DS. However, it has been observed that when VMware attempts to remove the snapshot created during a Druva job operation, and there was a snapshot present on the VM before the Druva job, snapshot stun may occur. Aug 19, 2011 · We have an issue where the snapshot stun is significant and can stop network access for several seconds. Snapshot removal triggered VMware snapshot consolidation of Veeam snapshot into the old snapshot from a month ago 7. If the snapshot fills the disk, you're basically pwned. VM Snapshot Backup Support May 17, 2017 · It could be the VM stun as the snapshot is merged/consolidated and SQL loses the n/work connection. I've talked to VMWare who told me to talk to our datastore vendor. 30 minutes later (during which the VM was stalled), VMware returned that the snapshot had failed. 5 with vShield endpoint activated get into a hung state during snapshot operat Sep 17, 2019 · Sometimes customers who use mirroring and VM snapshots to do their backup do run into mirror connectivity issues and failovers. During this stun, the guest OS is frozen, and so when it comes back, the system clock is behind. The only common trait is ; the same vm’s that were part of a recent migration are ones that are doing this. In some cases we have seen VM's unresponsive for for nearly an hour. Aug 4, 2020 · Stuns will also occur when a VMware snapshot is deleted. I have logged a call with VMWare and they have looked into it and determined that everything is working as designed (ie yes there will be a pause right at the start of the snapshot it’s the running memory being captured Virtual machines might stop responding during a snapshot removal due to a forced synchronous consolidation between the snapshot disk and the parent disk. Vm snapshot NO memoryBUT INCLUDING Quies. I'm not able to access VM at that time, not able no restart it, not able even to reset. The VM has one snapshot and has been running on it for over 72 hours. But the bigger VM (~1. VMware stuns (quiesces) the virtual machine (VM) when the snapshot is created and deleted. VM Loses Connection During Snapshot Removal Setting Specifying I/O Settings NetApp provides no representations or warranties regarding the accuracy or reliability or serviceability of any information or recommendations provided in this publication or with respect to any results that may be obtained by the use of the information or observance of Edit: Since not all applications respond to a request to quiesce their disk usage, there are only two totally safe ways to make a snapshot: take a memory snapshot so that the VM memory and disk comes back exactly to the point where it was 'stunned', mid disk write and all. When VEEAM backs-up the server it takes a snapshot, when the back-up is complete it removes the snapshot, this then causes the server to hang and loose connectivity for anywhere up to 1 hour, thus causing an outage to end users. The VM shows as being online in vCentre but it doesn’t show as having an IP address or that VMware tools is installed. This is the first thing I would check. Jan 29, 2021 · You can take a snapshot when a virtual machine is powered on, powered off, or suspended. maxIterations to 20 (or higher). Now that they can be, it makes sense to leverage that technology. This is NOT required for a database file backup. I never take snapshots with the memory as a backup. They provide information on VM stun cycles duration during snapshot commit operations, basically if VM remains stunned for a few seconds, this results in network drop in guest OS. Feb 23, 2016 · Application stunning during the snapshot process is a topic that often bubbles up in customer conversations on data protection for VMware environments. Oct 10, 2017 · The snapshot consolidation failed and my VM was unresponsive during the time it took to recover from that failure. VM snapshot INCLUDING memory AND Quiesc. Retry the backup at a time of lower activity for the guest VM. However, in some circumstances such as a VM with a large storage footprint, VMs consuming large amounts of storage IO, or storage that isn't fast enough, the VM stun can be disruptive. Jun 13, 2024 · VM snapshots can cause "stun moments," which are periods during which the VM is briefly paused to create the snapshot. 7. Delete All is all but guaranteed to stun the VM. Backups may be slower with quiescing. This is more common and quite troublesome in situations where heavy I/O servers (like Exchange for example) live on NFS datastores. For a highly transactional application like databases (in this case the Oracle DB), side effects can appear due to VM stun. I created VM snapshots for these systems a long time ago and forgot to delete them. Backup only the passive or a read-only server within the AAG, using Native SQL backups with RBS and/or VM level backups. These snapshots appear to the end-user as any other Feb 4, 2013 · I have the same problem wiht the time sync guest VM when i take a snapshot. asyncConsolidate. Jan 24, 2011 · VM snapshot removal stun is expected behavior of any Virtual Machine in VMware since VMware has to shift the active writes to disk from the snapshot file back to the base disks. Running into a strange issue with only about 3 VMs so far where a snapshot attempt or a vmotion will cause the VM to completely lock up and become unresponsive. Larger/more active machines are more likely to become stunned during snapshot removal, due to the relatively large amount of data that has to be merged back into the base disk. VMware - Defect ID: 77030 High VM Stun time during snapshot deletion or SVmotion failure on ESXi 6. When taking a memory snapshot, the entire state of the virtual machine will be stunned, stun time is variable. The snapshot size is small (sesparse file is 16GB big but du -h displays only 120MB being used), but during consolidation ESXi writes the whole time (10+ minutes) at 80-120MB/s to the storage array. - When a virtual machine backup jobs starts, a call is made into the vCenter to request a quiesced snapshot of the VM. These stun moments are particularly disruptive during the consolidation phase, where the snapshot data is written to disk. スタンというのは、文字どおり仮想マシンの『麻痺』を意味します。vmのスナップショットを削除するときに、i／o（インプット／アウトプット）が頻繁に発生しているほど、ホストに負荷がかかって起こってしまう、vm一時停止の現象です」 How Long is the Unstun Time for a Virtual Machine after a Snapshot Removal? Facts. For detailed explanation of snapshot removal issues, see VMware KB Article 1002836. Mar 11, 2016 · 4. Jan 4, 2018 · 1) Restore VM Snapshot 2) Run DiskShadow Revert. For Example: If the time taken to stun a VM during snapshot create with one virtual disk is X, then, multiplying with number of VMDKs sums up the total Checkpoint_Unstun required to complete Snapshot creation operation. The creation of the snapshot just stuns the VM for a second or so, which should never corrupt any data. highly depends on esxi build and how active the VM is. 0, the snapshot stun times are logged. Generally, just don't use snapshots on database servers. 5 TB) will get about halfway and lock up. What is the maximum stun time for the VM during vmotion operation, snapshot creation/deletion? Is there any setting to verify this? Is there anyway to reduce the stun time of the VM? Feb 12, 2025 · If no disks are using -00000X. Although the timing is coincidental, it How Long is the Unstun Time for a Virtual Machine after a Snapshot Removal? Facts. Not sure if you can with nutanix but most new arrays have a tie into veeam. In VMware Infrastructure 3 and vSphere 4. Internal memory is not included in the snapshot. Apr 28, 2015 · Let’s look at the scenarios in more detail one at a time, and discuss the use of “stun” in each case: Create a snapshot. - but the vm is shutdown. The number of VMDKs attached to the virtual machine impacts the stun time, the fewer, the better. 0 and above. The smaller VMs complete backups successfully. Mar 9, 2021 · タイトルの通りなのですが、vmのイメージバックアップ時のvmスタンの回避方法についてお聞きしたいです。 ・ESXI6. I was thinking about forcing a storage vmotion to true up any delta or split vmdk’s that could be causing a timeout on the snap. Mar 28, 2017 · It's a known issue with VMware that it performs what is called a "stun" during certain operations, such as vmotion, and snapshot create/delete. if a snapshot was taken. 5 days to complete. This is usually due to network interruption when the VM becomes “stunned” during part of the snapshot backup process and the stun time lasts longer than the time determined by the mirror QoS timeout. As part of the backup process, the software must stun the VM during different stages (particularly during snapshot removal). As a workaround the Cluster heartbeat sensitivity was increased to avoid the effect of the VMware Snapshot “Stun” . May 15, 2012 · The first thread specifically refers to performance issues and temporary disconnects due to a long snapshot removal process, not complete failure. Some VMs lose 3 pings. This occurs when the virtual machine is running a heavy I/O workload during snapshot consolidation. 1 seconds of stun time) Apr 1, 2025 · VMware snapshot with quiescing: When you perform the backup of a subclient, quiescing is performed automatically for the operating system and applications on the virtual machines in the subclient. Apr 28, 2015 · Now, we have understood VM stun and the steps for VM snapshots, and how the delta VMDK files are merged into a single disk. This would eliminate any VM stun completely and eliminate failover events, as long as they are associated with the STUN caused by VMware snapshot removal. Jun 4, 2021 · Every time when Veeam starting create backup, the VM(every time it's different VM) the VM become unavailable. More information in this KB article. Provisioning a Rubrik Cloud Cluster Elastic Storage creates a virtual Rubrik Cloud Cluster running in a virtual private cloud, providing data protection for hosts and applications. The issue is the snapshot grows as it sits and reconsolidation will "STUN" the VM. Later versions of VMWare at least significantly improve this so if you're still running 5. Nov 10, 2024 · The VM stun time to complete Snapshot creation operation directly correlates with number of VMDKs associated to a Virtual Machine. This is a known VMware issue that occurs with VMs on NFSv3 storage when the target virtual machine and the backup appliance reside on different hosts. Mar 1, 2016 · To minimize errors like guest crashes or orphan snapshots, we opted to build our own VSS agent that doubles as both requester and provider during the VSS coordination process. The other factor affecting VM stun is the speed of your storage. At Veeam Support, one of the most commonly raised support cases was for orphaned snapshots. I don't think it's a storage issue. After removing all the snapshots using the snapshot manager for that particualar VM, EVERYTHING returned to normal. log file for the VM for a message similar to the 影響を受けるVM保護メカニズムのstunは、VMスナップショットの作成時に設計されています。 回避 策： PowerProtect Data Manager VMware Protectionソリューションは、バックアップを実行するためにVMスナップショットを必要としない透過的スナップショットData Mover(TSDM)ソリューションを提供します。 Nov 21, 2011 · Slower than normal but it would NOT "stun" the VM when committing the snapshot and deleting it. log. A Rubrik cluster backs up a virtual machine by creating a snapshot of the virtual machine by using vMware APIs for Data Protection. Nov 9, 2023 · The affected VM protection mechanism stun is by design during the VM Snapshot creation. During this stun process the VM its OS cannot execute any operations and is essentially in a "stuck" state (e. This means vSphere will do more tries (iterations) to commit the snapshot files. When snapshots consolidate, they halve repeatedly until the last one where it pauses the VM stuns" it briefly. The snapshot that is created during this process is named VEEAM BACKUP TEMPORARY SNAPSHOT. CTK files used for CBT. Wait how does reverting a snapshot not stun a VM? Probably not exactly stun but the state of the VM is killed and started from the snapshot so there will be a moment in time where the VM appears to be stunned right? the stun may be the equivilant of 1-2 pings in time but the actual reason for the ping drop is because the esx host sends a RARP to notify the switches that the VM has moved to a new hosts so they know where to send the network traffic. It’s gigantic. However, I've never had a snapshot deletion go wrong or cause the VM to crash unrecoverably. I know it’s confusing because they use the same name but their technology is nothing alike. log shows the VM was stunned for a few seconds while deleting the snapshot: [YYYY-MM-DDTHH:MM:SS] In(05) vcpu-# - CPT: vm was stunned for ##### us Mar 16, 2021 · Start the Windows Virtual Disk service for the guest VM as described in the VMware KB article “msg. error-QUIESCING-ERROR” in vCenter Server (2069952). The vmware. 4. While the removal is taking place, the Virtual Machine becomes unresponsive. Dec 16, 2009 · 1. Jan 20, 2016 · After providing the VMware administrator with the event times it became obvious that the “Stun” effect of starting and then removing the VMware snapshot for the cluster server VMs was causing the issue. The sync time with Host and VMtools is uncheked and not configured in the VM. After doing a bit of research, it happens specifically during VM Snapshot creation when the VM is paused to allow the snapshot to create. Jun 13, 2023 · When a snapshot is taken during the quiescing process, it represents a consistent view of the guest file system state at a specific point in time . On the guest VM, verify that VMware Tools are installed and up to date. Jan 22, 2025 · When the the snapshot is created for a virtual machine, disks are closed in order to create delta disks and attach them to virtual machine. I read you are using Veeam. Orphaned snapshots were caused by VMware’s own failed snapshot commit operations due to unreleased VMDK file locks during VDDK operations. Not sure why anyone would want that, as we rarely even restore snapshot backups, but that would cause significant stun on larger machines. ureygf vdllkz iwpydhl brqck negwnh cji hzay hix euhw tujse