Slow Disk Access

[tmcnicho]

Let me start by saying this problem is quite frustrating :)

As you can expect, slow backups brought this problem to my attention. I have a 5.1 SP8 server that has local mirrored 9GB drives and then a number of SAN volumes coming from an MA8000 through Compaq HBA's.

Basically disk performance sucks...

I've used DPMETERM to test w/64KB blocksize...

The local mirrored array responds to DPMETERM @ 8MB/sec, I know these are old, but I expect better than that. When being backed up I am getting about 1.5MB/sec.

The volumes on SAN storage respond to DPMETERM @ 21-23MB/sec (I still expect better than this), backup speed slowly will move up to around 7MB/sec if I'm lucky.

Now... I was backing up through the network, so I decided to take that out of the equation. I let this system be a device server for my backup software (Syncsort Backup Express) so it can address a tape drive directly. The performance did not change, and in fact I think maybe got worse.

Also... I did some testing via network file transfers. A 680MB file took almost 2 minutes to transfer over a gigabit network, that is not right. It went slightly faster to a SAN volume, but not much. Copying the file back was about the same speed.

Something isn't right here, it's almost as is disk subsystems are being throttled.

Any help is much appreciated.

Thanks,
Tom