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HP Ultrium LTO and BE 8.0 compression not working

TechBiz Support
Occasional Contributor

HP Ultrium LTO and BE 8.0 compression not working

The ultrium drive and tapes should be able to backup 200 GB of raw data with hardware compressions enabled, but after a drive replacement the drive only backs up about 100 gb wich to me indicate that compression isn't working.

If I look in the BE log, it says that hardware compression is enabled:
======================================================================
Job Operation - Backup
Media operation - overwrite.
Hardware compression enabled.
======================================================================

I use the veritas driver on the tape.

Does anybody know what could be wrong?
5 REPLIES
TechBiz Support
Occasional Contributor

Re: HP Ultrium LTO and BE 8.0 compression not working

Sorry it's BE 8.5 and not BE 8.0 :)
Peter Mattei
Honored Contributor

Re: HP Ultrium LTO and BE 8.0 compression not working

Well, a 1:2 compression can only be achieved with highly compressible data.
If you let???s say backup ZIP files, you will not be able to compress anything!

If you think your data should be compressible I suggest you have a look at the following page talking about backup and performance.
http://h20015.www2.hp.com/en/document.jhtml?lc=en&docName=lpg50460

There are two tool mentioned
1. The Library and Tape Tools (LTT) and
Use it to check your tape environment
2. Performance Assessment tool (PAT)
Shows your backup performance and bottlenecks.

Cheers
Peter
I love storage
Leon Rosier
Respected Contributor

Re: HP Ultrium LTO and BE 8.0 compression not working

Did you run the tape drive configuration wizard after replacing the drive?
You should do this.

Leon
Curtis Ballard
Honored Contributor

Re: HP Ultrium LTO and BE 8.0 compression not working

Download the latest copy of HP StorageWorks Library and Tape Tools (3.3 as of now) which includes drive performance tests. You can use it to test you drive with data that has known compression ratios and see what happens.
TechBiz Support
Occasional Contributor

Re: HP Ultrium LTO and BE 8.0 compression not working

I downloaded the tools and ran a compression test, this ended with a success with a ratio over 2:1. At first the tool poped up with a messega telling me that hardware compression was disabled and asked me whether I would like to enable it, I did that and ran Veritas Device configuration again + a full backup of a server with Hardware compression if availeble otherwise software on. The log now shows software compression:

======================================================================
Job Operation - Backup
Media operation - append.
Software compression enabled.
======================================================================