Reverse incr backup and failures

[Henrik.Grevelund]

Hi,

I was wondering what happens to the VBK file if the reverve incr failes during backup.
The VBK file has been updated during the bakup.
Does it remove the changes, roll back, or leaves it in a inconsistent state, and maybe runs a full afterwards ?

[david.domask]

Hi @Henrik.Grevelund,

Veeam will try to roll it back on the next job run. In most cases where it's a veeam data mover agent error or other higher level fault, the automatic process can usually fix it. Failures due to things like network interrupts/soft power-downs also usually can be repaired by the same process. Hard IO errors (bad disk, hard power-downs) are a bit iffier as it really depends on what happened on the write, but it's still often recoverable.

Basically, the storage format has resiliency for such situations during the transformation processes (Reverse Incremental, Synthetic Full, Forever Forward Incremental Merge); if you hit LZ4 decompression errors or errors related to declared and actual crc are different, unfortunately it likely means the file is unrecoverable. There are still chances Support may be able to recover partial data, but it's not a guaranteed process if the backup files are at this point.

[Henrik.Grevelund]

Hi David,

Thank you for the answer. I was able to test it a little, and noticed it did the rollback.