On 11/9/[masked]:44 PM, Robert Gezelter wrote:
> Laird, Calvin, and Paul,
> It is well-known that RAID5, particularly rebuilds, can result in drive
> If one considers MTBF as a function of number of operations (rather than
> number of "running hours") this should not be surprising.
> RAID5 uses an extra volume as for parity. Thus, each and every time that
> one of the other volumes is written to, the parity volume must be
> updated. This results in a very high usage rate for the parity disk, and
> the resulting wear and tear leading to failure.
> When it was first proposed, RAID5 made more economic sense. Today, in
> many situations, it is far better to use mirroring configurations
> (so-called "RAID 0+1") to achieve performance and redundancy in many
I think that you're referring to how cheap (an large) hard drives have
gotten, in your last paragraph?
Given that, wouldn't the same rationale apply to use RAID5, but to _not_
bother rebuilding in the event of a problem, but rather migrate the
degraded RAID to an entirely new set of (tested) disks?
As for RAID 0+1, or RAID 10 - dropping two is (possibly) deadly. Perhaps
a bit safer than RAID5, but wouldn't RAID6 be preferable?
Thanks for your insights,