On 16/09/2010 23:41, Michal Soltys wrote:
On 10-09-16 00:03, Pol Hallen wrote:
additionally, in the event
of a disk failure, rebuilding a 6x1TB RAID5/6 array will take forever
and a day.
a nightmare...
very thanks for your reasoning.. I don't have enought experience about
raid and friends!
Pol
One remark - write intent bitmaps will make it perfectly fine (orders of
magnitude faster). I'm not sure how the feature looks from performance
point of view these days though.
It should be configured with a sensible block size; the default block
size is usually too small and spoils performance. I chose a 16MB write
intent bitmap block size after experimenting a while ago (have a look
for posts on the subject from me), on the basis that larger gave
diminishing returns for write performance and smaller (nearer the
default) impacted badly on write performance, but others have gone as
big as 128MB (again see the archives), but the default, while it depends
on the array size and metadata version, often damages write performance
for only a small benefit in recovery time.
In short, the default write intent bitmap block size works but is liable
to be suboptimal so you should consider tuning it rather than take the
default.
Cheers,
John.
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