Dual channel scsi

johnnyboy32 · 1 Aug 2010 at 09:21

I have 4 x seagate cheetahs and an Adaptec 39320 raid card. Will my best set up be the four drives in RAID 0 or will I get better performance by using two drives on each of the available channels on the Adaptec. I only have one cable so I will have to purchase another to take advantage of dual channel.

ubersonic · 1 Aug 2010 at 12:36

Is the 39320 plugged into a 64bit PCI slot or a standard 32bit one? if its in a 32bit slot then the max bandwidth available to the controller card will be 266MB/s and four cheetahs in raid 0 will bottleneck that under sustained transfer.

johnnyboy32 · 1 Aug 2010 at 12:47

Uber, it'll be plugged into a 64 bit PCI-X slot on a Tyan motherboard.

ubersonic · 1 Aug 2010 at 16:31

KK, you don't see many people running PCI-X systems these days, I have a PCI-X SCSI 320 controller in my rig but its only in a 32bit slot. I would recommend you put two drives per channel, if you put all four on one channel the will only be 320MB or bandwidth to go around and 4 drives will bottleneck on that (assuming 80MB/s+ sustained read per drive) whereas on separate channels they can consume up to 160 each without incident

johnnyboy32 · 1 Aug 2010 at 17:11

Thank you. Pardon my ignorance but will the four drives come up as one drive, even if they are on seperate channels. I have not had a dual channel card before and only have one cable at the moment. I assume on host raid I will be able to add all four drives to make one array.