What does bad chunks mean and how to dive into the source problem ?

[Fathi]

Hi,
I have a message about a bad chunk on my pbs dashbord. What does this mean ?

 

[ubu]

PBS stores your data in blocks (chunks) inside the .chunks directory your backup store.
There are checksums and when a chunk file is damages it will be detected by the verify job

 

[Chris]

Hi,
I have a message about a bad chunk on my pbs dashbord. What does this mean ?
View attachment 50975

Hi,
as correctly stated by @ubu this indicates that data corruption happened in one of you chunks. Please check your disks health and verify which snapshots are affected by this. It might be enough to perform a new backup and verify task for that snapshot group in order to recover the bad data. If the chunk contained data which is no longer available because it since changed on disk, the newer snapshots will verify just fine, but the old snapshots remain corrupt.

Make sure to use storage with build in redundancy such as ZFS and perform regular offsite backups.