[CentOS] PCI-X/PCIe RAID controller.

Sat Apr 9 14:08:40 UTC 2011
Christopher Chan <christopher.chan at bradbury.edu.hk>

On Saturday, April 09, 2011 09:14 PM, Drew wrote:
>> cheap scsi raid?  good luck.   maybe something on ebay, but then its
>> Caveat Emptor, and likely the raid batteries will be dead or dying.
>> What speed is your scsi backplane?  you can't get Ultra/320 speeds
>> across older backplanes that were designed for U80 or U160 speeds.  in
>> fact, I've had a few backplanes that were supposed to be U320 but only
>> worked reliably at U160 speeds, would get SCSI protocol errors when
>> pushed under high IO loads at U320.     64bit 33Mhz PCI will sustain
>> about 200MB/sec, which is about all you can get out of a single channel
>> of U160 or slower SCSI anyways.
> In that case there's no real point upgrading. :-) The drives are U160's.

The key is the backplane, not the drives. You should be able to get u320 
speeds if you have enough u160 drives.

> I was just hoping a slightly newer card might be available that'd give
> me a speed boost for cheap. :-)

Again, like John posted, it depends on whether your backplane(s) can 
feed the u320 card and whether its bus can take the bandwidth.