An error occured while taking snapshot

[nufael]

Hi,

I'm facing an issue to backup my VM due to this error:

Creating VM snapshot
Error: An error occurred while taking a snapshot: The parent virtual disk has been modified since the child was created. The content ID of the parent virtual disk does not match the corresponding parent content ID in the child.

Does anyone here has come across this issue before?

Regards

[Vitaliy S.]

Seems like you have modified the original virtual disk which this snapshot is referring to, thus you cannot proceed with the operation. Do you have any existing snapshots on the VM? Also please include your support case ID when posting about technical issue, otherwise this post will be removed due to forum rules violation. Thanks!

[nufael]

Hi Vitaly,

I run the job with multiple VMs. Seem like only one VM has an issue as mention earlier. And I believe there is no modification on the Virtual Disk. Can you explain in details what is the case if there is a modification in the Virtual Disk and how can I fix it. The things is, the problematic VM still running as usual like other VMs.

Regards

[Vitaliy S.]

Try to create the snapshot for this VM manually via vSphere Client and check if it has any snapshots present or not. BTW, the support case ID cannot consist of 4 digits, please post the full ID in the post. Thanks!

[nufael]

If i create the snapshot manually and it is available, can i proceed to re-run the backup without the said error?

Regards

[Vitaliy S.]

Yes, try to re-run your backup job, if you happen to see the same error message, then continue working with our support team.

[nufael]

Hi Vitaliy,

I came across the same problem with different error:

Creating VM snapshot
Error: An error occurred while saving the snapshot: Unable to save snapshot file.

Before we investigate further, this VM is an oracle RAC VM. Only this VM has an issue and I notice that the affected VM's has been shut down after the backup.

Don't you think it ts related to backup compatibility?

Regards

[veremin]

Error: An error occurred while saving the snapshot: Unable to save snapshot file.

Are talking here about manual snapshot creation? If so, one of the reasons might be lack of free space on the given datastore.

Don't you think it ts related to backup compatibility?

Backup operations should not have any effect on your ability to take snapshots.

Thanks.

[nufael]

- there is no issue during manual snapshot creation using vsphere client but there's an issue during veeam backup job as mentioned in the previous post

- I've a lot of space in my datastore which I believe there's not an issue related to vmware kb as posted by you

- So you're saying that there is no issue to backup ORACLE RAC VM in veeam backup platform?

[Vitaliy S.]

Yes, there should be no issues backing up this VM if you're able to create snapshot manually. If VM was shutdown, then you should investigate VMware VM logs for the reason why it did that. Please let our support team investigate the latest log files and assist you with this issue. Thanks!

[nufael]

Is there any issue in backing up vm running a share disk running oracle rac vm? Or do we need extra configuration to backup those type of vm?

[Vitaliy S.]

What kind of shared disk do you have? If VM can be snapshotted, then it can be backed up via vStorage API for Data Protection.

[dellock6]

If you are referring to the multi-writer VMDK suggested by VMware to deploy fully virtualized Oracle RAC, then no it's not supported, since this kind of disk cannot be snapshotted using VADP libraries. You should exclude the disk from the Veeam backups and use workarounds to backup the databases, like for example running RMAN and dump the database in a non shared disk.

Luca.

[nufael]

Hi All,

I think I need to rephrase on the previous comment. After checking with the team who support the Vsphere platform below are the summary:

- the problem persists only at the VM running Oracle RAC with 3disk shared with other nodes (multi-writer enable) and one disk (system/os disk) multi-writer disable

- I've read through article stated that it is unsupported to snapshotted VM with multi-writer enable but as mentioned by Luca we can exclude the multi-writer enable disk in backup job

- I've done that and only backup the system disk but the problem still persisted with; Error: An error occurred while saving the snapshot: Unable to save snapshot file.

Do you think it is possible to only take on the disk with multi writer disable or as long as the VM has a disk multi write enable, snapshot will no longer working with that VM?

Thanks

[dellock6]

Hi,
you can do a quick check: can you take a snapshot in vCenter of the same VM? If you get an error, is the same reason we cannot.
I'm not sure (out of office we no lab available), maybe the shared disk should also be configured as independent...

Luca.

[nufael]

vCenter don't have the capability to exclude disk from backup means it will do the snapshot for all disk in the VM and will resulting snapshot failed (I've tried few times). Since Veeam has the features to exclude disk from backup, i was thinking it will help me to resolve the multi-writer disk issue. But it also resulting the same error eventhough I'm exluding the multi-writer disk from the VM backup. Do Veeam has any other resolution to this matter?

Thanks

[Gostev]

Veeam disk exclusion skips processing certain disks once the snapshot has been created. However, actual VM snapshot is still performed by vSphere. Thanks!

[dellock6]

The only way to avoid a snapshot creation of a certain disk is to set it to independent in the disk properties inside vCenter, but the multi-writer disk has nothing to do with this configuration, is simply (and sadly for you) not supported by VADP libraries at the moment.

Luca.