On Thu, 2 Feb 2006, Matthias Urlichs wrote:
Hi, David Liontooth wrote:
We're wondering if it's possible to run the following --
* define 4 pairs of RAID 1 with an 8-port 3ware 9500S card * the OS will
see these are four normal drives * use md to configure them into a RAID
6 array
Hmm. You'd have eight disks, five(!) may fail at any time, giving you
two disks of capacity.
Ouch. That's not "very high" redundancy, that's "insane". ;-)
In your case, I'd install the eight disks as a straight 6-disk RAID6 with
two spares. Four disks may fail (just not within the time it takes to
reconstruct the array...), giving you four disks of capacity.
Yes, but then you (probably) lose hotswap. A feature here was to use the
3ware hw raid for the raid1 pairs and use the hw-raid hotswap instead of
having to deal with linux hotswap (unless both drives in a raid1-set
dies).
A net win, I'd say, esp. since it's far more likely that your two power
supplies will both die within the time you'd need to replace one.
But it's your call.
If you only need reliability and can spend a few extra disks, I didn't
find the setup so bad.
/Mattias Wadenstein
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