Topic: poor SCSI tape performance

[Nathan Price]

I have a SME 5.1.2 server with an LSI SCSI controller and a Sony AIT-1 drive for backups.  The drive is capable of up to 10MB/s but I am only getting 0.5MB/s.  Perhpas I have configured something wrong?  There are tweaks for IDE drives i.e hdparm; are there any for SCSI?

Any thoughts are appreciated.

[Shad Lords]

Actually AIT-1 drives are limited to about 3Mb/s native mode.  You might get better depending on compression.  If you do software compression you will not see above 3Mb/s.

I have 3 different AIT-1 driveshooked to a 2840U2W controllersand regularly get 169-170Mb/min = ~2.8Mb/s.  I would look at your controller.

-Shad

[Nathan Price]

Thanks for your input Shad.  2-3MB/s would certainly be better.  Any thoughts where to look for tuning the controller?

[Charlie Brady]

Nathan Price wrote:

>  2-3MB/s would certainly be better.

Don't forget that you also need to be able to pull data more quickly than that from the file system, and you need to be able to compress it that quickly too. IOW, your bottleneck could be your file system and hard drive(s), or could be your CPU.

>  Any thoughts where to look for tuning the controller?

The interface should self-tune.

Charlie

[Nathan Price]

I had thought about CPU and hard drive.  I don't think this is the problem as it is a 1.8G P4 with newer IDE hard drives.  I have turned on Multi-Sector, UDMA, and 32bit support through hdparm and my file transfers from the server seem fast enough to satisfy the tape.

It just seems that something is amiss with the SCSI setup.  Thanks for the input