Function Verify backup

S

simrsta

Member
Oct 25, 2022
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I have installed PBS
and I'm happy because it's easier to backup and faster

My question is, do I have to verify all my backup results for every backup?

If it is not verified, what will be the impact?

because I do backups for the database server every 2 hours because it is related to patient medical record data
 
simrsta said:
I have installed PBS
and I'm happy because it's easier to backup and faster

My question is, do I have to verify all my backup results for every backup?

If it is not verified, what will be the impact?

because I do backups for the database server every 2 hours because it is related to patient medical record data
Click to expand...
Hi,
a verification job makes sure your backup snapshots are still intact. How often and when you want to check this is up to you and your needs. Further, this depends on other factors as e.g. storage setup as well, as the storage itself can have some data corruption detection and healing mechanisms (e.g. when using a ZFS RAID).

Re-verification of at least once per month is however recommended. Details you can also find in the docs https://pbs.proxmox.com/docs/maintenance.html#verification
 
Chris said:
Hi,
a verification job makes sure your backup snapshots are still intact. How often and when you want to check this is up to you and your needs. Further, this depends on other factors as e.g. storage setup as well, as the storage itself can have some data corruption detection and healing mechanisms (e.g. when using a ZFS RAID).

Re-verification of at least once per month is however recommended. Details you can also find in the docs https://pbs.proxmox.com/docs/maintenance.html#verification
Click to expand...
oh ok at least one per month

In PBS, backups are always incremental, right?
because I backup every 2 hours
so just add the latest data


i already backup in Synology but need 2 hour every backup and only 1x backup perday
 
simrsta said:
oh ok at least one per month

In PBS, backups are always incremental, right?
because I backup every 2 hours
so just add the latest data


i already backup in Synology but need 2 hour every backup and only 1x backup perday
Click to expand...
Yes, since the backups are performed incremental by deduplicating chunks, the verification makes sure the already uploaded and therefore reindexed chunks are still healthy. Otherwise all the snapshots referencing a corrupted chunk are corrupted.

If a corrupted chunk is detected, the same chunk is reuploaded if encountered on the local source, thereby healing all the snapshots referencing it. If the local data changed however the snapshots referencing the corrupt chunk are not restorable. So catching data corruption early is desired.
 
Chris said:
Yes, since the backups are performed incremental by deduplicating chunks, the verification makes sure the already uploaded and therefore reindexed chunks are still healthy. Otherwise all the snapshots referencing a corrupted chunk are corrupted.

If a corrupted chunk is detected, the same chunk is reuploaded if encountered on the local source, thereby healing all the snapshots referencing it. If the local data changed however the snapshots referencing the corrupt chunk are not restorable. So catching data corruption early is desired.
Click to expand...
1720514813423.png

How long does an incremental backup take??
It's been 10 minutes but it's still processing

I see that network traffic is not running but the backup is still in process?
 
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simrsta said:
View attachment 71063

How long does an incremental backup take??
It's been 10 minutes but it's still processing

I see that network traffic is not running but the backup is still in process?
Click to expand...
Since this is a container, the PVE side will have to re-read and re-chunk the whole container filesystem, which depending on the data can take some time. Only chunks not known to the PBS host will be uploaded again.

There is an (still experimental at the time of writing) change-detection-mode which does allow to re-chunk only file payloads for files changed with respect to the previous backup run, further details for this can be found in this thread https://forum.proxmox.com/threads/pbs-client-change-detection-mode.150538/post-680876
 
Chris said:
Since this is a container, the PVE side will have to re-read and re-chunk the whole container filesystem, which depending on the data can take some time. Only chunks not known to the PBS host will be uploaded again.

There is an (still experimental at the time of writing) change-detection-mode which does allow to re-chunk only file payloads for files changed with respect to the previous backup run, further details for this can be found in this thread https://forum.proxmox.com/threads/pbs-client-change-detection-mode.150538/post-680876
Click to expand...
I make backups every 4 hours
but getting an error notification in prune
what do I have to do

1721353460020.png
 
I'm still a little confused about how to properly configure the verification jobs. I had posted before about yellow warning exclamation marks appearing next to everything in my repo before, but they came back. So I added a full verify job.

Does the way I have it configured here make sense?

I just added the weekly (sat @ 3:15am) job that does NOT skip verified snaps. The other job remains at "skip verify=YES and re-verify after 30d (which I assume will now never occur since the other job is weekly??) I tried to set it to "0" or blank but the UI does not accept that so I left it at 30.

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