Throttling Options

[collinp]

Is there an option to throttle the number of backups running against a CSV? Microsoft Support told me that 2 VM's running on 2 different hosts from 2 different backup jobs should never run at the same time against the same CSV. In other words, only one snapshot should be performed against a CSV at a time. Not sure if this is true or just best practice and referencing DPM's serialization by CSV.

I notice that when backing up with the Hardware VSS that it regulates multiple snapshots against the same CSV by saying "Resource not ready: snapshot". But when the Hardware VSS fails over to Software VSS when backing up in Onhost mode I see that the Microsoft CSV Software provider is tried regardless, and doesn't check if there are other snapshots running against the CSV (at least I don't believe it does since it never gives me a message that snapshot already in progress). See attached image for an example of this scenario where the Software VSS provider is failed over to and tries to run but unsuccessfully. I still think that I experience issues though when both Software VSS providers try to snapshot at the same time, even though they fail.

My questions are, what happens in these scenarios. Are 2 snapshots allowed at the same time against the same CSV in these scenarios?:

1) 2 jobs which are set to use the Software VSS provider and run at the same time against the same CSV
2) 2 jobs which are set to use the Hardware VSS provider but failover to the software VSS provider at the same time against the same CSV
3) 1 job is set to use the Software VSS Provider and the other job is set to use the Hardware VSS provider and they run at the same time against the same CSV

Here is the image url: https://picasaweb.google.com/cannonc34/ ... 5480379586

[veremin]

1) Hardware providers can work with several snapshots simultaneously – if you have several jobs that work with the same volume, you can run them in parallel. And the error you’ve mentioned seems to be related to the usage of Software Provider, instead (probably, you’re using WS 2008).

2) It depends on what version of Windows Server you’re using. In case of 2008, you will not be able to start several jobs working with the same volume simultaneously due to the redirected mode. However, it’s no longer the case with 2012.

Thanks.

[collinp]

I am user Hyper-v 2012. So there is no way to throttle the number of simultaneous snapshots against a CSV?

[veremin]

It’s not possible to regulate this setting via Veeam Backup and Replication. Instead, you can set the number of concurrent task that Hyper-V backup on/off/host proxy can perform and, thus, avoid multiple jobs accessing one CSV in the same time.

However, as mentioned above, there are no issues related to running several jobs against one CSV in parallel.

Hope this helps.
Thanks.