On 21/04/2009 02:05, Johannes Segitz wrote:
On Tue, Apr 21, 2009 at 2:52 AM, John Robinson
<john.robinson@xxxxxxxxxxxxxxxx> wrote:
There's no redundancy but it's still the RAID-5 4-disc layout with 3 data
and 1 parity, the parity on a different disc in each stripe. In your case
with a missing disc, for 3 stripes in 4 you have 2 data and 1 parity. Of
course the parity is having to be calculated when you're writing, and
whatever would be written to your missing disc is being discarded.
you're right, i didn't think of that. But calculating an xor isn't really
a big deal (especially with the aes on top of it) so i still can't see why
it's so slow
No nor can I, especially since your `time` output shows a very modest
amount of system time; it may be worth trying fewer layers (i.e. no
encryption and/or no filesystem) to eliminate them, or monitoring with
other tools like iostat to see if you can get to the bottom of it.
Cheers,
John.
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