On Tue Feb 05, 2013 at 01:49:07PM +0000, Brian Candler wrote:

On Tue, Feb 05, 2013 at 01:40:14PM +0000, Brian Candler wrote:

quoted

On Tue, Feb 05, 2013 at 01:02:37PM +0000, Robin Hill wrote:

quoted

quoted

1. The UUUU_ and [22/21] suggests that one disk is bad, but is that true?
And if so which one?

No, that's normal. A RAID5 (or RAID6) array is created in a degraded
form, then the last disk(s) are recovered (it's the quickest way of
getting the array ready for use).

Ah I see. Thank you.

The odd thing is, if I make a RAID6 I get [UUUUU] with no underscores?

# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md127 : active raid6 sdy[23](S) sdx[22] sdw[21] sdv[20] sdu[19] sdt[18] sds[17] sdr[16] sdq[15] sdp[14] sdo[13] sdn[12] sdm[11] sdl[10] sdk[9] sdj[8] sdi[7] sdh[6] sdg[5] sdf[4] sde[3] sdd[2] sdc[1] sdb[0]
      61532835840 blocks super 1.2 level 6, 512k chunk, algorithm 2 [23/23] [UUUUUUUUUUUUUUUUUUUUUUU]
      [>....................]  resync =  0.0% (850232/2930135040) finish=1607.7min speed=30365K/sec
      bitmap: 22/22 pages [88KB], 65536KB chunk

unused devices: <none>

Looks like my mistake. The mdadm manual page indicates that it's only
RAID5 that is done this way. RAID6 will just do a full resync to
generate the parity.

Cheers,
    Robin
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