James Lee wrote:
>From a quick search through this mailing list, it looks like I can
answer my own question regarding RAID1 --> RAID5 conversion. Instead
of creating a RAID1 array for the partitions on the two biggest
drives, it should just create a 2-drive RAID5 (which is identical, but
can be expanded as with any other RAID5 array).
So it looks like this should work I guess.
I believe what you want to create might be a three drive raid-5 with one
failed drive. That way you can just add a drive when you want.
mdadm -C -c32 -l5 -n3 -amd /dev/md7 /dev/loop[12] missing
Then you can add another drive:
mdadm --add /dev/md7 /dev/loop3
The output are at the end of this message.
But in general think it would be really great to be able to have a
format which would do raid-5 or raid-6 over all the available parts of
multiple drives, and since there's some similar logic for raid-10 over a
selection of drives it is clearly possible. But in terms of the benefit
to be gained, unless it fails out of the code and someone feels the
desire to do it, I can't see much joy to ever having such a thing.
The feature I would really like to have is raid5e, distributed spare so
head motion is spread over all drives. Don't have time to look at that
one, either, but it really helps performance under load with small arrays.
--
bill davidsen <davidsen@xxxxxxx>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
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