Re: Drive fails & raid6 array is not self rebuild .

	Hello Neil ,  Inline .

On Fri, 9 Sep 2005, Neil Brown wrote:

On Thursday September 8, babydr@baby-dragons.com wrote:

quoted

 	Hello All ,  Is there a documented procedure to follow during
 	creation or after that will get a raid6 array to self
 	rebuild ?

I suspect a kernel upgrade would do the trick, though you don't say
what kernel you are running.
You could probably kick it along by removing and re-adding your spare:
 mdadm /dev/md_d0 --remove /dev/sdao
 mdadm /dev/md_d0 --add /dev/sdao

(And I assume you mean 'raid5' rather than 'raid6', not that it
matters..)

	Sorry ,  yes I meant raid5 .

	My kernel version is .
root@devel-0:/ # uname -a
Linux devel-0 2.6.12.5 #1 SMP Fri Aug 26 20:09:46 UTC 2005 i686 GNU/Linux

	When I try to do the remove I get .
root@devel-0:/ # mdadm /dev/md_d0 --remove /dev/sdao
mdadm: hot remove failed for /dev/sdao: Device or resource busy

	I should also have 3 other drives that are spares .  I could
	try hot remove on one of them .  See at bottom the output of
	mdadm --misc -Q --detail /dev/md_d0
	Which is showing no spare drives ?  And I built it with 4
	spares

root@devel-0:~ # cat /etc/mdadm.conf
DEV /dev/sd[c-l] /dev/sd[n-w] /dev/sd[yz] /dev/sda[a-h] /dev/sda[j-s]
ARRAY /dev/md_d0 level=raid5 num-devices=36 spares=4 UUID=2006d8c6:71918820:247e00b0:460d5bc1

	 c-l is 10 devices (one is dead 'e' leaves 9) .
	 n-w is 10 devices
	 yz  is  2 devices
	aa-h is  8 devices
	aj-s is 10 devices
		----------
		40 devices given in mdadm.conf
		-1 dead device .
		----------
		39 devices
		36 devices used (per /proc/mdstat)
		----------
		 3 devices for spares .

quoted

# cat /proc/mdstat
...snip...
md_d0 : active raid5 sdc[0] sdao[40] sdan[34] sdam[33] sdal[32]
sdak[31] sdaj[30] sdah[29] sdag[28] sdaf[27] sdae[26] sdad[25]
sdac[24] sdab[23] sdaa[22] sdz[21] sdy[20] sdw[19] sdv[18] sdu[17]
sdt[16] sds[15] sdr[14] sdq[13] sdp[12] sdo[11] sdn[10] sdl[9] sdk[8]
sdj[7] sdi[6] sdh[5] sdg[4] sdf[3] sde[2](F) sdd[1]
       1244826240 blocks level 5, 64k chunk, algorithm 2 [36/35]
[UU_UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU]

/dev/md_d0:
        Version : 01.02.01
  Creation Time : Sun Aug 28 17:46:59 2005
     Raid Level : raid5
     Array Size : 1244826240 (1187.16 GiB 1274.70 GB)
    Device Size : 35566464 (33.92 GiB 36.42 GB)
   Raid Devices : 36
  Total Devices : 36
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Thu Sep  8 06:26:10 2005
          State : clean, degraded
 Active Devices : 35
Working Devices : 35
 Failed Devices : 1
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           Name :
           UUID : 2006d8c6:71918820:247e00b0:460d5bc1
         Events : 5308

    Number   Major   Minor   RaidDevice State
       0       8       32        0      active sync   /dev/sdc
       1       8       48        1      active sync   /dev/sdd
       0       0        0        0      removed
       3       8       80        3      active sync   /dev/sdf
       4       8       96        4      active sync   /dev/sdg
       5       8      112        5      active sync   /dev/sdh
       6       8      128        6      active sync   /dev/sdi
       7       8      144        7      active sync   /dev/sdj
       8       8      160        8      active sync   /dev/sdk
       9       8      176        9      active sync   /dev/sdl
      10       8      208       10      active sync   /dev/sdn
      11       8      224       11      active sync   /dev/sdo
      12       8      240       12      active sync   /dev/sdp
      13      65        0       13      active sync   /dev/sdq
      14      65       16       14      active sync   /dev/sdr
      15      65       32       15      active sync   /dev/sds
      16      65       48       16      active sync   /dev/sdt
      17      65       64       17      active sync   /dev/sdu
      18      65       80       18      active sync   /dev/sdv
      19      65       96       19      active sync   /dev/sdw
      20      65      128       20      active sync   /dev/sdy
      21      65      144       21      active sync   /dev/sdz
      22      65      160       22      active sync   /dev/sdaa
      23      65      176       23      active sync   /dev/sdab
      24      65      192       24      active sync   /dev/sdac
      25      65      208       25      active sync   /dev/sdad
      26      65      224       26      active sync   /dev/sdae
      27      65      240       27      active sync   /dev/sdaf
      28      66        0       28      active sync   /dev/sdag
      29      66       16       29      active sync   /dev/sdah
      30      66       48       30      active sync   /dev/sdaj
      31      66       64       31      active sync   /dev/sdak
      32      66       80       32      active sync   /dev/sdal
      33      66       96       33      active sync   /dev/sdam
      34      66      112       34      active sync   /dev/sdan
      40      66      128       35      active sync   /dev/sdao

       2       8       64        -      faulty spare   /dev/sde


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