Need for verify in remote PBS?

[julian]

I have a primary PBS with SSD syncing to a remote PBS with HHD. Running the verify task(s) on the primary is fast, but on the remote is quite slow.

I wonder if it is strictly necessary to do a verify on the remote too? As this is just a 1 on 1 copy of the primary. If on the primary all is OK then it should be OK on the remote too, all data transfer itself is already checksumed by the transport layer, or am I missing something? Remote also is on ZFS.

How do others manage this?

 

[Johannes S]

I have a primary PBS with SSD syncing to a remote PBS with HHD. Running the verify task(s) on the primary is fast, but on the remote is quite slow.

What means fast and what means slow?
I wouldn't go without verify in case data is corrupted or manipulated after the Transfer.

 

[omgs]

I have a primary PBS with SSD syncing to a remote PBS with HHD. Running the verify task(s) on the primary is fast, but on the remote is quite slow.

I wonder if it is strictly necessary to do a verify on the remote too? As this is just a 1 on 1 copy of the primary. If on the primary all is OK then it should be OK on the remote too, all data transfer itself is already checksumed by the transport layer, or am I missing something? Remote also is on ZFS.

How do others manage this?

Also, verifying in every pbs node helps to increase safety of stored data, because there could be issues in local datastore (it happened to me).

 

[tcabernoch]

I agree with the prior responses, but I have a similar situation.

My fast (SSD) PBS is up front doing the backups.
My slow (virtual) PBS is in back with the big slow storage and small cpu/ram.

So ya, my slow PBS can run verify jobs for 17 hours.
There's a lot of data to scan, and its a turd of a VM running directly on TrueNAS Virtual Machine feature.

IDK, I still schedule Verify daily where I can, but I have one installation where I've reduced it to a weekend run.
I use "Skip Verified" and "Reverify after 7 Days".

 

[omgs]

AFAICT, the verification applies to local storage in each pbs, so you can have a "source" verification but a "faulty" storage in a remote. So, each pbs should have its own verification policy. I think that if you need to reverify, first check the storage from time to time. If there are no issues with the underlying filesystem, there should be no need for reverification. Just saying the theory, for if there was a wrong assumption.

 

[tcabernoch]

Hmm. omgs I'm not sure I follow your line of thought, or if I do, I'm not sure I agree with it. Maybe I just don't understand your point.

Regardless, in my use case, the storage is in fact suspect. The remote PBS is a turd of a VM running on a Supermicro TrueNAS as both the storage and hypervisor. There's several layers of virtualization that data synced from another server, possibly even other datacenter, could be corrupted in. And the Supermicro has failed in the past. A bit of checking seems to be in order ... so long as it isn't impacting other operations.

 

[omgs]

What I mean is that, as long as the underlying filesystem where the datastore resides has no issues, I think you don't need to reverify. The time you find out there's a problem with the filesystem, after repairing, you may need to check everything, regardless the source where it came from.