mdadm help reduce number of disks

can anyone please help me on reducing the number of disks from a raid5 raid array
i've done the following steps

umount /dev/md0
mdadm --fail /dev/md0 /dev/sdc1
mdadm --remove /dev/md0 /dev/sdc1

mdadm --grow /dev/md0 --raid-devices=3
it says  "Cannot reduce number of data disks (yet)."
Anyone have idea?

Thanks

原帖由 cma019 於 2009-4-12 13:56 發表
can anyone please help me on reducing the number of disks from a raid5 raid array
i've done the following steps

umount /dev/md0
mdadm --fail /dev/md0 /dev/sdc1
mdadm --remove /dev/md0 /dev/sdc1

mdad ...


AFAIK, there are no simply  way to reduce number of disks from RAID5 in traditional technology of RAID.

Maybe you should build another RAID 5 to store this data, or add another disk to re-assemble the old RAID.

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I guessed so too. Thanks for your reply though

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I have not done it before but I think I read it somewhere. You need to move the data from the member disk you want to detach first.

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