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View Full Version : Effect of an 18GB LVD on same chain as RAIDed 9.1GBs?



TaxiDriver
02-21-2002, 05:39 PM
I have two 9.1GB Seagate 10K LVD Cheetahs in a RAID-0 on a Miles2. I'm thinking about either adding a third identical drive for speed and power, or a different 18GB LVD. Would it be possible to add the 18GB LVD to mirror the striped 9.1GB machines? Otherwise I'm going to add the other 9.1GB and use a 30GB ATA100 FW external for backup.

ricks
02-21-2002, 06:43 PM
Hey TD,

When you set up a mirror, the bus will pass data at the speed of the slowest volume on the mirror. Your RAID0, is probably faster than most any single drive. If you for instance add a drive that gives you 30MB/second by itself and your RAID0 gives you 52MB/second, when you add the mirror via the single drive that's how fast your whole RAID0+1 will be, 30 MB/second less any overhead.

I bought four identical drives to build my RAID0+1 for exactly that reason. If I want it to be faster I will go to 6 or 8 drives.

Rick

TZ
02-21-2002, 06:43 PM
The new 18GB 10k Cheetah is rated at 50MB/s which is more than the Miles2 can provide in Vintage PCI Macs or Ultra2. I would look at that. I have a 10k Cheetah from last spring that only offers 35MB/s maybe at its best. They have definitely improved the 18GB and 36GB and for reasonable prices.

Gregory

dragon_x
02-22-2002, 12:48 AM
I second ricks motion. GET IDENTICAL DRIVES. While different drives can work in theory you are only asking for problems. Maybe not now, maybe not a month from now, but six months - 9 months later you might find your data is TOAST! http://www.macgurus.com/ubb/eek.gif

I have not setup any RAID1S OR RAID0+1s but I have had issues RAIDing different drives for speed (stripe). I have heard of issues with the same drive but different revision/firmware ... I have to CudaIVs in my QuickSilver... but they are very different S/N Firmware since I bought on this past summer and the system shipped with a Cuda in late November. Besides I would want a 3rd drive before RAIDing.

So how is that RAID 0+1 configured ricks? Classic Mac OS? SoftRAID? What?


------------------
The Cost Of Freedom:
Every bit of energy.
Every ounce of courage.
Every drop of blood.

Sic Semper Tyranus!

ricks
02-22-2002, 01:51 AM
soooo,

I am currently playing speed test games with the four AtlasIIIs to see just how fast and in what config they work best. I hope that when SoftRAID releases SoftX it will do the job for us. I am only interested in OSX for the future on my Quicksilver so I haven't stored anything permanently yet on the Atlas array.

Rick

TZ
02-22-2002, 04:19 AM
On the different revisions, I bought one X15 in September, rev. 0002 and now they are 0004 and I swear there is some subtle differences (even the sound and how they act) is noticeable.