Backup Jobs and readers/streams?

[hutchingsp]

We're running Galaxy 7.0 with SP4a.

I have a couple of Windows File System iDataAgents that are each around 3tb in size.

Each is set to use 6 data readers.

I have a schedule that kicks off a full backup job for both clients, the backup device is a dual drive LTO3 library, with the Storage Policy configured for 2 streams.

What I'm finding is that both jobs kick off at the same time and "Scan".

One finishes first and starts to backup - at this point six streams are writing.

The other client finishes and then starts backing up using the remaining 2 streams.

Here's the problem - when the first client finishes backing up, the second client doesn't "grab" the available streams and continues to backup (slowly) using only 2 streams.

I noticed if I manually suspend it and then resume, that it starts using the maximum of 6 streams.

I've always found resource tuning a bit of a black art, as I often seem to find what I'd call "spare" backup streams/capacity being unused with jobs queueing rather than maxing out the library.

Any suggestions welcome and appreciated.

 

[jjjon]

I had a similar problem (LTO3 Library) which was resolved by setting Contention Resolution from SCSI-2 to SCSI-3. Under the Properties of the library in the Drive tab.

Jon

 

[hutchingsp]

Thanks Jon - Galaxy seems to be full of all these little options with fairly casual explanations in the Help.

Do you know what impact that would/should have please and why?

Our library is connected via a SAS HBA.

 

[jjjon]

As long as your SAS library can support SCSI-3, I don't think you'd see much impact. I know the only impact I saw was the (seemingly) better handling of the reservations.

Jon