Bit off topic : It should go faster than this...

Hi All,

I am an Oracle DBA but was recently asked to sort out a SAS system running on win 2000 which was really struggling with its batch taking over 20hours. Nobody knows much about SAS round here though I could tell that the system was terribly IO bound. It was decided to throw hardware at the problem and I specified (with compaqs help) a high end disk subsystem.

I realise that this is not oracle but was hoping that somebody here may be able to help...as I was...

The system is as follows.

Compaq DL580 4 x 2ghz Xeons
Twin Smart Array 5300 4 Channel Raid Controllers ( each connected to a separate IO Bus) 256MB Cache on each.
Four SW4354 Storage Shelves, each with two Ultra3 SCSI buses and fourteen 72GB Ultra3 15K RPM hard disks.

These are configured into 2 x 26 Drive Raid 1+0 arrays. (We have a global hot spare in each storage enclosure). Each array is connected to its own 5300. Stripe size of 64k.

Each of the 4 channels on the 5300's are capable of 160mb/s giving 640mb/s across each 5300.

When all this was set up I got the boys who configured it to copy a 2gb file from one array to the other. Now I think that 24 secs is pretty slow and would have thought 4-8 secs would be more like it. 24 secs indicates an actual write speed of approx 80mb/s.

Any Suggestions? Am I being unrealistic in expecting this subsystem to be able to write at about 260mb/s (20mb per spindle?)? Is something misconfigured or is this the best I can expect?

Thanks

Ralph Received on Wed Jun 11 2003 - 08:15:16 CDT