Raidtest/3Ware 6000 Throughput
cswiger at mac.com
Thu Mar 16 19:08:18 UTC 2006
Don O'Neil wrote:
> I would have thought I would at least see the raw single drive throughput,
> plus maybe a bit more.
When choosing RAID levels, you are making a tradeoff between performance,
reliability, and cost. Choosing RAID-5 means you value performance the least of
If you prefer... ...consider using:
performance, reliability: RAID-1 mirroring
performance, cost: RAID-0 striping
reliability, performance: RAID-1 mirroring (+ hot spare, if possible)
reliability, cost: RAID-5 (+ hot spare)
cost, reliability: RAID-5
cost, performance: RAID-0 striping
If you've got enough drives, using RAID-10 or RAID-50 will also improve
performance compared to stock RAID-1 or RAID-5 modes.
> I've benched these drives independantly at 20+
> MB/second... Is the 3ware card really slowing things down that much with the
> RAID-5 overhead?
Yes. It will be less noticeable with big transactions, and more noticeable with
lots of tiny ones.
> What "real HW RAID-5" controller would you suggest? I'd like to stick with
> IDE/ATA since I have a bunch of drives already.
Maybe the 3ware 9500S -4 or -8...?
> Am I maybe CPU bound, or have another issue?
You're probably I/O bound, not CPU bound.
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