On 05/25/2012 07:35 PM, Jim Klimov wrote:
> Sorry I can't comment on MPxIO, except that I thought zfs could by
> itself discern two paths to the same drive, if only to protect
> against double-importing the disk into pool.

Unfortunately, it isn't the same thing. MPxIO provides redundant
signaling to the drives, independent of the storage/RAID layer above
it, so it does have its place (besides simply increasing throughput).

> I am not sure it is a good idea to use such low protection (raidz1)
> with large drives. At least, I was led to believe that after 2Tb in
> size raidz2 is preferable, and raidz3 is optimal due to long
> scrub/resilver times leading to large timeframes that a pool with
> an error is exposed to possible fatal errors (due to
> double-failures with single-protection).

I'd use lower protection if it were available :) The data on that
array is not very important, the primary design parameter is low cost
per MB. We're in a very demanding IO environment, we need large
quantities of high-throughput, high-IOPS storage, but we don't need
stellar reliability. If the pool gets corrupted due to unfortunate
double-drive failure, well, that's tough, but not unbearable (the pool
stores customer channel recordings for nPVR, so nothing critical really).

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