ultrium 230 on l2000

[Haim Fridman]

We have purchaed an ultrium 230 tape drive and connected it to L2000 via the ultra wide scsi2 interface that is on the core io board together with the nic.
We have tried to backup 140G
of data with tar and with ftio but only 100G backed up
with transfer rate of 13m/sec.
I understand that lto 230 shud backup up to 200g with transfer rate of 30m/sec .
Why it isn't so on my system?

[Eugeny Brychkov]

Hi,
native data transfer speed is 15mb/s, but with compression ratio 2:1 it can be 30mb/s.
So, please check if you backing you data up with compression turned on. In addition, for optimal perfomance and long life of drive it is recommended that throughtput to be at least 15mb/s (for Ult230 and 7,5 for Ult215). Please check SCSI bus for errors and PDC for bus speed setup to be 'unlimited'
If you have compression turned off right now I would tell that perfomance is not bad. Tune system to raise perfomance to at least 15mb/s.
Eugeny

[Leif Halvarsson_2]

Hi

Tar and perhaps not ftio is not fast enough to stream a LTO drive at full speed. You need a high performance backup program (for examplse OmniBack).

Check the data you backup. Don't expect high performance if backing up millions of small files (unless with disk image backup).

Check compression ratio of your data, use "compress" command on some typical files. Compress uses the same algorithm (LZW) as the drive. You need at least 2-1 ratio to get 30MB/s.

Disk/filesystem performance. You need a very fast disk system to stream a LTO drive. With OmniBack (or other high end products) you can back up several filesystems in paralell to one drive.

You should read the document "How to optimize performance of HP Ultrium tape drives".

http://www.hp.com/products1/storage/products/tapebackup/ultrium_tapedrives/ultrium230/infolibrary/whitepapers/ultperfpress.pdf

[Haim Fridman]

Hi

1. How can i check if the compression is turned on ?

2. How can i check the scsi bus and set the PDC bus speed to unlimitedt?