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Tylor
07-19-2001, 01:04 PM
Ok, I've ruled out ATA completely since it has limitations, and risks getting stuck with that stutter in vintage PCI machines. And I can't put it inside my new RAID case I'm building out of a IIfx. 9-drive capacity so far! http://macgurus.com/infopop/emoticons/icon_biggrin.gif

Anyway, I'm going to set up LVD RAID(s) with Seagate drives. I want to have enough speed to saturate the 2940U2B card, and PCI bus limitations in my 9600, but I also need masses of disk space(80GB+), for digital video work with heavy editing and compression.

The kicker: Small budget (always the problem that crops up, huh?). I've been looking around, and I could manage to get the space I need with 5 or 6(or more, maybe) Barracudas RAIDed, but not overspend myself. I was wanting to know if that many Barracudas in a Level 0 RAID could match, or come close to, the speed of 2 or 3 10K Cheetahs in the same kind of RAID? This is assuming they're all the latest generation, or course.

I'm being dragged off on vacation, so I probably can't be back before Sunday night. Everyone give me your opinions, recommendations, etc, and I'll post replies as soon as I get the chance. Thanks!

[This message has been edited by Tylor (edited 19 July 2001).]

dragon_x
07-19-2001, 07:36 PM
Well -

3 10K cheetahs should come close to if not over the limits of the 2940U2b card. So for the bare min - you could get 3, 36GB drives. For greater speed you could get another 2940U2b and multi-plex the cards/drives - basically giving you ULTRA160 type bandwidth (due to your dual PCI controller architechture). You could then go with 4, 36GB 10K Cheetahs or 4, 18GB 10K Cheetahs... or maybe just 2, 36GB Cheetahs (but then you probably wont saturate the bus).

My first 10K Cheetah was fast. I think I'm almost used to them now. I've set up a lot of RAID-0. They are usually 7200RPM 2, 3 or 4 drive arrays. I've never setup a 10K Cheetah RAID - that should ROCK! http://www.macgurus.com/ubb/cool.gif Even at the 'slow' 10K RPM speeds...

The only downside to multiplexing (although I've never done this) is that you need to get DOUBLE cabling. Also at the speeds you want you should not skimp on cables - if you can help it.

Not sure how much you would save by going with Barracudas since you would need more drives to start to equal the Cheetahs. I would rather get fewer matched pair cheetahs than more cudas. The great thing about SCSI is if they start to get slow, just add some more drives.

------------------
Life in the fast lane leads to:
The Resteraunt At The End Of The Universe

kaye
07-19-2001, 09:00 PM
I'm with d_x, get the 10k or 15k Cheetahs. As you add more drives with a single 2940U2B, your sustained reads will continue upwards, but sustained writes will peak at around 40MB/s. Dual 2940U2B (slots 1 and 4) will overcome this sustained write limitation. I don't have any 2940U2B cards, nor do I know how well two of them would coexist, but that is how Miles2 or dual Miles2 performs in my PTP. k