Cannot backup nas share to catalyst store

[filippoAdb]

Case #07483555 — File share backup job on StoreOnce repository fails

I created a new Catalyst store on Hpe StoreOnce. I would like to use that store as repository for a nas share backup job.
According to documentation the infrastructure is fully supported but the backup job fails from the first time.
The error is something like this:
04/11/2024 10:32:24 :: Processing \\myNasShare\SharedDird Error: Failed to dispatch repository file sessions resource request. Requested amount of file sessions (26) is greater than the maximum amount available (21)

I perfecly know StoreOnce has limitations on maximum number of opened file sessions, but it seems to me there is no way to throttle the amount of file sessions B&R wants to use. I put every available parameter to the minimum.

[foggy]

What kind of StoreOnce is it? Is it VSA? The only case when StoreOnce could have that low file session limit is VSA with a low amount of memory. The lowest for hardware is 48 sessions for the old 2700, which is more than the requested 26. So either you have some tasks running in parallel eating the sessions or try to increase the appliance memory.

[filippoAdb]

Veeam B&R is version 12.2
StoreOnce is VSA.
I could increase the memory of a few GB (from 24 to 28) and the number of available sessions went above 26. After that an unstructured data backup job was successful.

I have been using StoreOnce Vsa as a repository for virtual machine backup jobs for months and I didn't have problems with file sessions.
It seems weird that 26 file sessions are needed when you backup a small file share. What happens when you backup a big one ?
I searched carefully on the available documentation, but find nothing about this 26 sessions limit, which is very worrying.

[foggy]

VM backup is different and has a session scheduling mechanism + some checks to prevent the creation of jobs that would require more sessions than the storage is capable of. For NAS Backup, it was assumed that the array has at least 64 sessions as whatever is less is either VSA (using which as a backup target is, anyway, not the best practice) or very old EOL hardware (as I mentioned above).

[filippoAdb]

For NAS Backup, it was assumed that the array has at least 64 sessions

Is it written somewhere in the documentation ?
Isn't it possible to force B&R to use less sessions ?

is either VSA (using which as a backup target is, anyway, not the best practice)

Is it your experience-based opinion or is is stated officially ?

Recently we spent lots of $$$$$ on the backup infrastructure thinking it was a good one, discovering it is out of best practices is quite frustrating, we will have to complain with our reseller.

[filippoAdb]

The small folder on the nas I used for test contains static data, files which are rarely modified.
The backup is scheduled once a day and for some days it was successful with "Backed up 0 files and 0 folders (0 B)"
Now it is successful on Retry 1 with the same result "Backed up 0 files and 0 folders (0 B)"
The first execution fails with error: "Failed to dispatch repository file sessions resource request. Requested amount of file sessions (34) is greater than the maximum amount available (30)"
The internal mechanism of B&R are becoming to me darker and darker.
Anyway it is useless to try to explain what is happening, which is weird, the conclusion is clear, it is not possible to use Storeonce vsa as a repository for file share backup job.
As fas as I know this severe limitation si documented nowhere.

[foggy]

It seems that the possible limitations are not mentioned in the NAS Backup documentation at the moment. Overall, deduplication appliances have never been recommended as a primary backup target without careful performance considerations; this is described in our reference architecture. If we're talking about VSA, it is even less recommended as it can be lost entirely with all the backups in case your virtual infrastructure gets compromised.

That said, I believe there should be registry values to decrease the number of file sessions required at the expense of job duration, so you can ask support for help here.