Why Does Sync Job Inherit Verify State

[ericz]

I'm setting up two PBS servers to support a PVE cluster in Washington (WA). The PBS servers are in two different states (PBS-WA, Washington) (PBS-OR, Oregon). PBS-OR is the off-site backup for PBS-WA. Therefore, PBS-OR has a sync job to copy PBS-WA to PBS-OR.

When the sync on PBS-OR completes, I'm surprised to see that the "Verify State" column of the Datastore: primary / Content view shows many green checkmarks. It appears that PBS-OR is inheriting the verification status of PBS-WA. Is this correct? If so, why is that safe?

Since PBS-OR and PBS-WA are physically separate storage their bit rot (1) is independent of each other. It seems to me that PBS-OR's Verify State should indicate the result of verification tasks on PBS-OR's drives, not PBS-WA's drives.

It is recommended that you reverify all backups at least monthly, even if a previous verification was successful. This is because physical drives are susceptible to damage over time, which can cause an old, working backup to become corrupted in a process known as bit rot/data degradation. -- https://pbs.proxmox.com/docs/maintenance.html#verification

 

[sw-omit]

I don't use PBS, but one thought:
Wouldn't the sync itself be the verification, so this check being there being correct?

During/After a sync from WA to OR, it would know that the (checksum of) the data on WA and OR are the same, so the data is verified and a checkmark is placed, would be my guess at least.

Also, 90% of the time if you have an in-house and an off-site backup, that off-site backup is more to catch if the in-house backup-devices fails/is "lost", so on the off-site you're usually more interested in the more recent backups (for if the source-data is lost at the same time) which are checked each sync. Unless of course if you have more storage-space (for the long-term storage) on the off-site location, then of course you would want to run verification on the (especially older) backups.

Others who do use PBS feel free to chime in of course, but this is just my 2 cents.