Backup Error after Hardware/ESXi Version Upgrade

Hi Rico,

The VSS writers failure clearly identfies that the problem is related to quiesced snapshot processing by VMware. This may happen only during specific hours during a day especially during peak hours (when manual snapshot works -> backup will also work). Probably there is some side activity performed on either the ESXi host or on some other VM on it which causes extensive CPU/RAM host resources consumption.

Note that Acronis Backup for VMware has a special option added (available in the latest 10535 build) to workaround such VMware-related issues: you can define amount of automatic snapshot retries under Backup Options->Error handling->"Re-attempt the failed VM processing". If this doesn't help and all snapshot attempts fail then you should definitely check what happens to host at the time when the backup is about to start to investigate the issue further.

Thank you.

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Best regards,

Vasily

Acronis Virtualization Program Manager

 Hi Vasily

I have noticed also that after the creation of a manual snapshots through vCenter VSS writers of vm change the status of timeout to no fault. I use the error handlich with 5 retrys after backup failure (same problem).

One Question: How much memory is required for the host to take a snapshot? The reason i ask that is because the max. memory of the host has changed too.

I have 16 GB RAM on the Host side and the available free space is now after migration only 512 MB or less. Before i changed the host hardware i had 24 GB Host RAM and 4 GB available free memory. Is it possible that the problem is caused by not enough Host memory?

Best regards

Rico

Hi Rico,

In fact there is no such strict RAM value that I'm aware of (probably VMware can advise - see troubleshooting recommendations) - all depends on particular machine state, how resources consuming are DBs operations, how much VSS requires to successfully create a volume shadow copy, etc. In general yes the RAM insufficiency may be the root cause (one of possible causes).

Thank you.

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Best regards,

Vasily

Acronis Virtualization Program Manager

 Hi Vasily

I performed some tests yesterday. There are no errors if i take a snapshot via vCenter. Backups with Acronis still fails. In the Event Viewer of Windows i see the following error message: VSS Error 12298 (maybe a disk I/O problem).

Than i make some more tests with the result that high I/O in the VM causes Backup Error. I scheduled a backup at that time when low I/O exists and the Backup was sucsessfully.

The only problem now is, what has changed in the VM since the Upgrade?!

Thanks for your help.

Best regards
Rico