On Fri, 21 Aug 2009, Tim Cook wrote:
Raid10 won't provide as much protection. Raidz21, you can lose any 4
drives, and up to 14 if it's the right 14. Raid10, if you lose the wrong
two drives, you're done.
On the flip side, the chance of loosing a second drive during the
recovery interval is much less with mirroring since only one drive
needs to be read in order to support the resilver and there is far
less mechanical action and I/Os involved.
If you make sure that you have a spare drive available to the pool,
then the spare drive can be resilvered and take over while you sleep,
minimizing the risk.
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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