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LTT 4.1 - Inconsistent results when running Backup pre-test

JLHughes
Frequent Visitor

LTT 4.1 - Inconsistent results when running Backup pre-test

I'm experiencing extremely poor performance trying to backup to a new MSL/Ultrium 960 library. To troubleshoot the problem I'm running the Backup pre-test from LTT 4.1. to try and isolate my bottlenecks.

The media server I'm running the test on is a dedicated Media server. There is no other activity on this server when I run the test.

When I first ran the test I saw a whopping 7MB/s. Not believing my system could be that slow I tried again and saw 29MB/s. On my third and subsequent runs I'm seeing 80MB/s. Why would I see this ramping effect when running this utility?
5 REPLIES
Dylan W
Advisor

Re: LTT 4.1 - Inconsistent results when running Backup pre-test

Could you have been running other processes at the same time as the previous tests? You would want to ensure that the removable storage service is disabled. Also make sure that you have one Ultra 320 SCSI card for each Ultrium 960 drive. Backup Program services should be stopped when using LTT, to ensure that any backup processes do not call on the tape drive during the test as well.
JLHughes
Frequent Visitor

Re: LTT 4.1 - Inconsistent results when running Backup pre-test

Dylan,

For clarification, the host is SAN attached as is the MSL library with the LTO drives.

While there were no other applications actively running, I did have associated Netbackup services running. Do you think this would cause an erratic test?
avik
Valued Contributor

Re: LTT 4.1 - Inconsistent results when running Backup pre-test

when you say dedicated media server, where is the data your backing up located ? in another machine on the network ?

Were you backing up the same set of files all the times ?

What about the master server ? Please remember that all image catalogs are still maintained by the master server.


avik
Valued Contributor

Re: LTT 4.1 - Inconsistent results when running Backup pre-test

Please ignore my comments, I was under the impression that your doing the tests in Netbackup.
Dylan W
Advisor

Re: LTT 4.1 - Inconsistent results when running Backup pre-test

Yes -- before running LTT tests always stop Veritas services and the Removable Storage service.

I would suggest this website for optimizing ultrium drive performance.

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=lpg50460

Run the PAT test at the bottom of the page to learn the perfomance speed of the server to the drive.

Also see this document for cabling recommendations.

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c00023650