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TigerKR
09-01-2001, 02:04 PM
From http://www.softraid.com/setup.lasso :

SCSI Tips:
2 SCSI cards or 1 dual channel card?
For small numbers of drives, placing the two drives on separate channels will not increase performance. Often performance will be slower with smaller I/O transfers. The reason is that a two channel card has additional latency from the SCSI bridge chip which allows both SCSI channels to work together. This added overhead translates into latency, which can slow small I/O transfer times on striped volumes.

TigerKR
09-01-2001, 02:09 PM
I am setting up a 2 drive 10,000 RPM Ultra160 internal RAID on a Dual800. Since I will not be using any other SCSI devices at all, it seems that I should not bother to get a dual channel SCSI card. According to softraid, if I put the HDs on the diff channels, I will get worse performance than if I have both of the drives on a single channel. This would mean that if I was to get a dual channel card, the second channel would be a waste, since I'm not going to use more drives, and I'm not going to use other scsi devices.

How's my logic?

kaye
09-01-2001, 08:32 PM
If you can wait a couple of days, I am about to put a UL3D and a couple of the latest X15s in a DP800. The holdup is I want to cool those two drives, one going on the left side bay and one in the center bay, and I haven't yet figured out how I want to do it.

I can try the striped RAID one on each channel and both on one channel and post. I tend to trust the SoftRAID info but some of it is obviously older than other info of theirs. I don't know about your reference. Maybe. k

kaye
09-03-2001, 02:37 AM
T,

Finished the 2nd gen 18GB X15 with UL3D tests in a QS DP800. Results below, but quick and dirty, 2 drives striped on one channel is only a hair slower than on dual channels. More drives would be a different story. So you want to be sure that there are no dreams/plans for more drives. Even the addition of a single drive, not part of the RAID, would be more elegantly handled on the other channel. Otherwise go for the UL3S.

My UL3D is running firmware 1.50 because 1.62 and 1.63 were slower. I have not tried 1.64 but will tomorrow.

ATTO EPT, 8MB, no System Disk Cache, HFS+:
PR-107.34, SR-058.86, PW-095.43, SW-060.58MB/s (One G2 X15 on UL3D)
PR-138.35, SR-112.64, PW-120.60, SW-115.45MB/s (Two G2 X15 on one channel, UL3D)
PR-205.50, SR-112.74, PW-123.94, SW-117.14MB/s (Two G2 X15 on two channels, UL3D)

MB5:
Disk-4500, Pub Disk-3875 (One G2 X15 on UL3D)
Disk-5413, Pub Disk-4394 (Two G2 X15 on one channel, UL3D)
Disk-5421, Pub Disk-4412 (Two G2 X15 on two channels, UL3D)

k

kaye
09-03-2001, 06:19 PM
ATTO firmware 1.64 is faster. For instance:

ATTO EPT, 8MB, no System Disk Cache, HFS+:
PR-205.50, SR-112.74, PW-123.94, SW-117.14MB/s (Two G2 X15 on two channels, UL3D, firmware 1.50)
PR-135.84, SR-113.70, PW-132.85, SW-117.78MB/s (Two G2 X15 on two channels, UL3D, firmware 1.64)

MB5:
Disk-5421, Pub Disk-4412 (Two G2 X15 on two channels, UL3D, firmware 1.50)
Disk-5473, Pub Disk-4511 (Two G2 X15 on two channels, UL3D, firmware 1.64)

k

drallen
09-03-2001, 07:30 PM
Kaye,

Are those numbers for FOUR cheetahs on two channels or two single Cheetahs on two channels?

Mark

kaye
09-04-2001, 01:35 AM
Mark,

Two single 2nd generation X15 Cheetahs (ST318452LW) on two channels, one on each channel. Am going to leave one in the QS and reinstall the other in the PTP. I have a Burly full of X15s, six configured with three per channel in the Burly) to attach to the UL3D in the QS. k

drallen
09-07-2001, 09:02 AM
Kaye,

Thats wild. Your numbers for your 2nd generation, two Cheetah X15 RAID 0, w/ UL3D card are the same for my FOUR 1st generation X15 Cheetahs, RAID 0, hooked up (internal) to an Adaptec 39160 in my G4 733.

What can you do with FOUR 2nd generation X15s?

Mark

sauria
09-07-2001, 09:35 AM
I assume that RAID arrays are still not bootable on Quicksilver?

jorge
09-07-2001, 09:40 AM
correct,

we still cannot boot off an Array in Quicksilver.

Maybe, just maybe OS 10.1 will change that.

j

kaye
09-07-2001, 03:34 PM
Mark,

I don't know about four G2 X15s. I just ordered six of the Gurus but they are all backordered and magician says the pipeline has dried up.

My Burly configured as dual channel with six G1 X15s (three per channel) attached to the UL3D in the QS, OS9.1, UL3D firmware 1.64, HFS+, yada yada, ...:

ATTO EPT, 8MB, No System Disk Cache
------------------------------------------------------
PR-219.84, SR-155.28, PW-194.84, SW-183.86MB/s

k