Setting LTO Tape sub-levels needed?

[hcpit]

Hello,

Have Backup Exec 12.5 SP3 and am using LTO 4 Tapes but I'm getting around a 1.1 -1.3 compression ratio with hardware and software compression enabled - Apparently this is normal but I was expecting more. The tapes are being indentified as LTO @ 800gig. Seeing as these tapes are LTO 4, should I be setting them as LTO 4 in the sub-level or is it best to leave Backup Exec to choose and detect what it is - Is there another level I should be using - It's an HP LTO 4 drive with Tandberg AutoLoader. I seem to be filling tapes really quickly recently.

Also should I be moving new tapes into Media Pools or leaving them as scratch and letting backup exec pick one to use when the time comes to backup the data to tape?

Thanks

[CraigV · Accepted solution]

Hi,

That is quite normal for LTO4.  They are 800GB native, and 1.6TB compressed. So for all intents and purposes, until compression is set, they will always be capable of holding 800GB. No changing that in BE.
Compression itself...you won't get compression on files that are already compressed (like *.jpg; *.zip etc), so in the real world, a 2:1 rate isn't always achievable.
However, look at changing the compression from Software, to Hardware, otherwise Software. That is a setting on the job itself, and then see if it makes any difference.
For myself, the best I have got was 1.6:1 on an LTO3 tape.
Personally, I let BE decide which tapes are scratch and assign them to a pool, especially if they are new. Obviously if your library/autoloader is partitioned, the tapes in those partitions will be assigned to the pool that they are directed at.

Laters!

[hcpit]

Ok thanks for that. I have the jobs set to Hardware then software if available but still only get around 1.2:1 Compression. I'll also leave them in scratch. Thankyou :)

[CraigV]

Great, glad it helped.