LTO slow backup in Tru64 unix

[Dileep_4]

Hi,
We have installed LTO 460 Drives in Alpha server GS80 system . We have noticed that we are geting only 10 MB/S transfer rate. Our disk controllers are DS-KZPCC-CE Raid controller and the LTO controller is Ultra 2 KZPCA-AA Controller. Could you please provide your solution to improve the backup speed

[Kurt Beyers.]

What block size are you using? Increase it till 256 kb, then the througput of the Ultrium2 will increase as well.

The speed depends as well on the type of data you are writing to the tape. If it is an ordinary file system backup with a lot of small files, 50 GB/hour will be an upper limit. If it are large database files (a few GB for each file), then you will go up to 100 GB/hour (if your SCSI card isn't a bottleneck).

best regards,
Kurt

[Dave Dewar]

Hi,

We provide a good performance trouble shooting guide on hp.com for tape drives. Link below:

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

There is also a version of LTT for Tru64 that has some inbuilt performance tools for checking memory to tape and disk to memory transfer rate to help identify bottlenecks in the system. This tool is referenced in the performanceguide above.
Here is a link to the tru64 stuff

http://h20000.www2.hp.com/bizsupport/TechSupport/DriverDownload.jsp?pnameOID=238676&locale=en_US&taskId=135&prodSeriesId=238671&prodTypeId=12169&swEnvOID=1048

Cheers,

Dave Dewar