+7Now this is just for my own curiosity. When Backup Jobs complete, Veeam runs Health Checks on the backup files to check for any corruption on the vbks.
What happens if the VBR server goes offline whilst a Health Check job was in progress? Does it carry on from where it left off, or does it start the whole process again?
Additionally, would it affect the vbk files in any way?
Best answer by MicoolPaul
Hey, health check is actually a lot more complex than how it sounds on the surface.
Some key points: it’s checking the latest restore point, not the latest file, so if the health check is done on the day a VBK is made, yes it’s just checking the VBK, but if it’s an incremental for example, it will have to read some blocks from the VBK and other incremental files to read all relevant blocks for the restore point.
If there is no corruption detected, it will be a read only operation. However in the event corruption IS detected, Veeam has to trigger some logic, if the VBK has corrupted blocks, it will strike the whole backup chain as corrupt, if an incremental file in the chain (i.e. not the latest incremental) is corrupted, all subsequent points in the chain AND the corrupted incremental file are marked as corrupted. If it’s just the latest file, then just that file is marked as corrupted. There’s also validation against the metadata, not just the blocks themselves.
It also behaves slightly different if you use reverse incremental due to the way the files are structured.
Once Veeam has detected the corruption, upon job completion it fails in an error state and then the job will retry as a separate session in an attempt to fetch the missing data and rebuild the latest restore point, this is key as well, as we’re only checking the validation of the latest restore point, that’s Veeam’s goal, to protect your RPO of your latest backup, we can’t go back in time and fix older points anywhere near as easily, but we have a good chance to fix the latest one.
And as for your other question if the health check stops because VBR goes offline, it has to start again.
For more information read: https://helpcenter.veeam.com/docs/backup/vsphere/backup_health_check.html?ver=110
+23Hey, health check is actually a lot more complex than how it sounds on the surface.
Some key points: it’s checking the latest restore point, not the latest file, so if the health check is done on the day a VBK is made, yes it’s just checking the VBK, but if it’s an incremental for example, it will have to read some blocks from the VBK and other incremental files to read all relevant blocks for the restore point.
If there is no corruption detected, it will be a read only operation. However in the event corruption IS detected, Veeam has to trigger some logic, if the VBK has corrupted blocks, it will strike the whole backup chain as corrupt, if an incremental file in the chain (i.e. not the latest incremental) is corrupted, all subsequent points in the chain AND the corrupted incremental file are marked as corrupted. If it’s just the latest file, then just that file is marked as corrupted. There’s also validation against the metadata, not just the blocks themselves.
It also behaves slightly different if you use reverse incremental due to the way the files are structured.
Once Veeam has detected the corruption, upon job completion it fails in an error state and then the job will retry as a separate session in an attempt to fetch the missing data and rebuild the latest restore point, this is key as well, as we’re only checking the validation of the latest restore point, that’s Veeam’s goal, to protect your RPO of your latest backup, we can’t go back in time and fix older points anywhere near as easily, but we have a good chance to fix the latest one.
And as for your other question if the health check stops because VBR goes offline, it has to start again.
For more information read: https://helpcenter.veeam.com/docs/backup/vsphere/backup_health_check.html?ver=110
+21Yes it will try the health check at the next job run based on the schedule set. See here - https://helpcenter.veeam.com/docs/backup/vsphere/backup_health_check.html?ver=110
+7Thank you for that great explanation
+7Yes it will try the health check at the next job run based on the schedule set. See here - https://helpcenter.veeam.com/docs/backup/vsphere/backup_health_check.html?ver=110
Thank you!
+23Happy to help!
+11Mr.
From Veeam and I quote “During the health check, Veeam Agent performs a CRC check for metadata and a hash check for data blocks in the backup file to verify their integrity. The health check helps make sure that the restore point is consistent just like
Note: Health check are only performed during the first job run! With this in mind, when an attempt is not successful, the VBR performs the health check during the last job retry in any case. If the health check detects corrupted data, Veeam Backup & Replication completes the backup job with the Error status and starts the health check retry process.
The health check itself is started only during the backup job session or the job retry session if the backup job session has failed. Which this and the answers above, your question should be answered!
+23If only answering these questions correctly counted towards my next VMCE
+11If only answering these questions correctly counted towards my next VMCE
I know right 
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