On Wed, 2002-09-04 at 13:55, Charles Lockhart wrote: > MonMotha wrote: > > > What kind of SCSI? > > The drives are ultra3, but while the array controller supports both > ultra2 and ultra3 drives, it makes everything run at ultra 2 speeds, or > something like that. I read it somewhere in their spec but now I can't > find it. >
What kind of data writes will you be doing? Mostly sequential, or random? I think modern SCSI drives (and even IDE drives) can sustain 40MB/sec sequential with only a single disk. What kind of speeds do you get with a single disk on that SCSI controller? At AMDMB we found one particular SCSI RAID controller (AMI MegaRAID) to be extremely terrible. In a RAID 1+0 configuration with four disks, we were somehow getting only 5MB/sec. Even after dozens of reboots and hours on the phone with AMI tech support, we were unable to fix the situation and moved to an Adaptec controller. Alan Cox's diary mentioned something similar about a year ago. He said something about throwing out his AMI MegaRAID controller and using Linux software RAID instead. He got much better performance that way.
