Compaq Smart Array 5300 performance question

[Vos]

We've got the following server:

- Compaq DL580 w/ dual pIII 900mHz CPUs
- Compaq 14 drive enclosure (model 4LEE)
- HP Smart Array 5302 RAID controller with 256MB of cache

We are doing large data transfers to the drives within the drive enclosure and getting very poor performance (~1-2mb/s). When we tried the same data transfer to the drives in servers internal drive cage we'd get double that.

So we upgraded the Integrated Smart Array controller to a new Smart Array 5302/256 and are getting blazing performance to the internal drives, but not much better at all to the external drives.

The internal drives are RAID1, and the externals are in 2 different RAID5 arrays. I realize the write performance of RAID5 is slower, but is really that slow?

Any ideas? Our SCSI cable is about 6' too long, any chance that would have any affect?

Thanks in advance

There are 10 types of people in the world,
those who know binary, and those who don't!

Vos

 

[gtackett]

Perhaps with Raid 5 you would benefit from the larger cache of the 5304? (I assume that you have battery-backed cache so that it is enabled for writes.)

We are just starting to try out a Smart Array 5304, but on an OpenVMS Alpha system, so I can't claim to know much about them yet...

 

[fraxx]

When you say your SCSI-cable is 6' too long, do you mean it's actually 6 feet longer than the supported maximum? If so, it could very well be a problem. At U320 speed, signal integrity is critical.
/charles