Re: Test with raid 6 software

On Wed, Jan 30, 2008 at 01:52:49PM +0100, Pol Hallen wrote:
I've 8 sata disk on raid 6 software (debian stable).

For purpose test I stopped 3 disks of the array.
^^^^
NOTE WELL: The md(4) man pages says that raid6 can handle the failure of
any 2 disks. You pulled 3. Good way to hose the array.

Now I rebooted and I tring to re-assemble the array but without successful..

mdadm -A /dev/md0
mdadm: /dev/md0 assembled from 5 drives and 3 spares - not enough to
start the array.

cat /proc/mdstat

Personalities :
md0 : inactive sdb[0](S) sdi[10](S) sdk[9](S) sdj[8](S) sdf[4](S)
sde[3](S) sdd[2](S) sdc[1](S)
3907091968 blocks

unused devices: <none>

Consider the data there are on the raid, and there aren't any disks
failure, is there a way to re-assemble the same raid and maintan the data?

Considering that this is a test, there should be no concern over data.
You did a backup prior to this test?

You hosed the RAID6 array by pulling 3 disks. The spares only help if a
spare disk can get syncd before a third disk died.

So, no, you have to make a new raid and restore from backup.

Doug.


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