Compression on VTL (Virtual Tape Libraries)

[McChikenhanger]

Hi guys,

 

Wondering if any Linux gurus out there can help me out. I have been playing with Quadstor VTL installed on top of CentOS 7 to test different backup software and how they would write to tapes. In this case the Quadstor VTL is giving the function of Virtual Tapes.

 

After weeks of trying I finally figured out how to install everything and I got a working rig. However, the thing I'm trying to figure out is that compression seems to be enabled somewhere either on the VTL Software or on CentOS 7 somewhere, and I need to turn it off, as I think it' messing up some of the backup jobs. I had 8 Gigs of data suddenly become only 1 Meg on the tapes.

 

Any help is greatly appreciated, oh Linux Masters.

[Geoff]

If you select 'hardware compression' in the backup utility then the VTL will compress. So turn that off there.

Other possibility is that you have dedupe enabled in your storage pool. You can turn that off in the VTL settings for the Storage Pool.

[McChikenhanger]

Hi Geoff.

 

Yes I did have Deduplication on the VTL, but I managed to turn that off. The issue was that the VTL was still compressing the files, and there was no easy way of turning it off at the VTL level.

 

But I think I have figured out how to do it since then.

 

Thank you for your reply.

[Geoff]

No, it will do what the backup software tells it to do (IIRC because this is required by specs). So you need to turn it off in the backup client.

[McChikenhanger]

Ah weird. Because I implemented something on the VTL, and now the files are no longer compressed. I was disabling compression on the Backup Softwares, but the VTL on a few of them was forcing the Virtual Tape to have Compression enabled. And there was no option to disable it from the Windows Server