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Re: Ultrium 960 (LTO 3) performs very slow write speeds

 
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RPDEIT
New Member

Ultrium 960 (LTO 3) performs very slow write speeds

Hi,

We recently purchased a Ultrium 960 to replace our existing Ultrium 460 to improve speed and space. We have a 3U rackmount kit to house the tape drives therefore I removed the existing 460 and replaced it with the new 960. The rackmount unit which contains the 960 is connected to a HP G4 DL380.
We are using Brightstor v11.5 to backup our system. Before we replaced the drive the backups were taking a bit over 4 hours to complete. After installing the new 960 tape unit the same backup job is taking around 18 hours to complete. I am still reusing the LTO 2 media we had in our rotation scheme but I canтАЩt see that causing this sort of speed differences.

Can anyone suggest what may be causing this as I would have expected the speed to increase not decrease (or be the same at minimum).

Thanks
6 REPLIES 6
Satish M.S.
Valued Contributor
Solution

Re: Ultrium 960 (LTO 3) performs very slow write speeds

Hello:

*Now the DL380 Prolaint G4 does not come with a suitable embedded SCSI controller card. So is the Ultrium 960 direct SCSI attached to an isolate/PCI-X HBA? If so, what kind of a SCSI HBA is it?

More info: http://www.hp.com/products1/storage/compatibility/tapebackup/ISS/Detail/16-0024-0059.html

Next, is the Hardware compression enabled on the Ultrium 960? This is again done via the Backup s/w, i.e., in this case the BrightStor.

Further, since you are experiencing a performance issue, kindly run the Library and Tape Tools (L&TT) diagnostic utility that can be downloaded from:

http://h20000.www2.hp.com/bizsupport/TechSupport/DriverDownload.jsp?pnameOID=406731&locale=en_US&taskId=135&prodSeriesId=406729&prodTypeId=12169


Before you run L&TT, kindly ensure that all the backup services pertaining to BrightStor are stopped and Removable Storage disabled (if running Windows). Run a read/write test to get an estimated transfer rate.

Also, run the PAT test - Performance and troubleshooting. For more info. click on

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=lpg50460&jumpid=reg_R1002_USEN

Thanks

Satish
RPDEIT
New Member

Re: Ultrium 960 (LTO 3) performs very slow write speeds

Hi,

Thanks for your speedy response.

I have connected the tape unit directly to the VHDCI SCSI port on the back of the DL380 and configured the SCSI cabling to embedded simplex SCSI mode. This worked fine with the Ultrium 460 for around 1 year. Quoted from the HP site ├в The HP ProLiant DL380 G4 does not support the HP StorageWorks Ultrium 960 internally. You may configure this server with an external drive or the appropriate rack option.├в I am using the rack option here so it should be ok.

I also read that the following are the compatible controllers so this is potentially the problem.
268351-B21 - Dual channel Ultra320 SCSI HBA
374654-B21 - Single channel Ultra320 SCSI HBA G2
284688-B21 - Dual channel Ultra3 SCSI HBA *

Luckily I have a spare Ultra 320 dual channel HBA in the store room but unfortunately I can not install it to test until l tomorrow as the server is heavy utilised.

I will install the new card and post the results tomorrow.

Thanks.
RPDEIT
New Member

Re: Ultrium 960 (LTO 3) performs very slow write speeds

Hi,

I installed an Ultra 320 SCSI card and then tested the tape unit using the L&TT tool. The drive is now performing properly.

Thanks for the tip, that solved our problem.
Richard Bickers
Trusted Contributor

Re: Ultrium 960 (LTO 3) performs very slow write speeds

What you did should work OK so something's gone a bit screwy in the process.

Couple of quick things you can try (I assume you've checked all your cabling etc - the 960 is U320 so should be using the U320 cable).
* Using HP's LTT (www.hp.com/support/tapetools), pull a support ticket for the drive (see help for details) and check; the Drive Health -> Device Analysis output to see if there are any warnings about SCSI configuration. You can see what rate has been negotiated between the host and the drive at Drive Configuration -> Interface.
* Also using LTT, run a Device Performance test to isolate the issue to the drive end and actually measure the data rates you are getting.

If you save the ticket, zip the directory and attach it to this thread then we can see what the drive thinks is going on. Best time to pull the ticket is just after the backup. You could do a short one for this - 10 mins of activity should give us 'steady state'.

Regards, Richard (LTT team)
It's more interesting when it's gone wrong
Satish M.S.
Valued Contributor

Re: Ultrium 960 (LTO 3) performs very slow write speeds

Hi RPDEIT:

Glad I could be of assistance. Cheers:)

Satish
RPDEIT
New Member

Re: Ultrium 960 (LTO 3) performs very slow write speeds

Thanks all.