[[PageOutline]]

 * [http://piro791.blog.so-net.ne.jp/2008-11-07 mdadmでソフトRAIDを領域拡張してみる（RAID 5編）：ぴろにっき：So-netブログ]
 * [http://elsidion.blogspot.com/2008/04/linuxraidraid6mdadmman128mbraid5.html つねおの怠惰な非日常: Linux Software RAIDのオンライン容量拡張の検証]

 = make RAID5 disk 5 -> 7 =
 == original devices ==
 * mitty@raid5:~$ sudo fdisk -lu /dev/sd?
{{{
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1              63     2097215     1048576+  fd  Linux raid autodetect
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1              63     2097215     1048576+  fd  Linux raid autodetect
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1              63     2097215     1048576+  fd  Linux raid autodetect
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sde1              63     2097215     1048576+  fd  Linux raid autodetect
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sdf1              63     2097215     1048576+  fd  Linux raid autodetect
}}}

 == create /dev/md0 with 5 disks ==
 * mitty@raid5:~$ sudo mdadm --create /dev/md0 -n5 -l 5 /dev/sd[bcdef]1

 * mitty@raid5:~$ cat /proc/mdstat
{{{
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdf1[4] sde1[3] sdd1[2] sdc1[1] sdb1[0]
      4194048 blocks level 5, 64k chunk, algorithm 2 [5/5] [UUUUU]

unused devices: <none>
}}}
 * mitty@raid5:~$ sudo mdadm -D /dev/md0
{{{
/dev/md0:
        Version : 00.90
  Creation Time : Sat Jun  4 20:48:11 2011
     Raid Level : raid5
     Array Size : 4194048 (4.00 GiB 4.29 GB)
  Used Dev Size : 1048512 (1024.11 MiB 1073.68 MB)
   Raid Devices : 5
  Total Devices : 5
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sat Jun  4 20:48:30 2011
          State : clean
 Active Devices : 5
Working Devices : 5
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : b49fdd73:9af2093f:0dfb77a3:1c88c57c (local to host raid5)
         Events : 0.34

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       81        4      active sync   /dev/sdf1
}}}

 == add to mdadm.conf ==
 * mitty@raid5:~$ sudo mdadm -Ds
{{{
ARRAY /dev/md0 level=raid5 num-devices=5 metadata=00.90 UUID=b49fdd73:9af2093f:0dfb77a3:1c88c57c
}}}
 * mitty@raid5:~$ sudo sh -c "mdadm -Ds >> /etc/mdadm/mdadm.conf"

 == mkfs and mount ==
 * mitty@raid5:~$ sudo mkfs.xfs /dev/md0
 * mitty@raid5:~$ sudo blkid /dev/md0
{{{
/dev/md0: UUID="15329342-a08c-4658-9b9d-53568eef427d" TYPE="xfs"
}}}

 * mitty@raid5:~$ sudo mkdir /var/raid
 * mitty@raid5:~$ sudo mount /dev/md0 /var/raid/

 * データが壊れないことの検証用データ
  * mitty@raid5:~$ sudo dd if=/dev/urandom of=/var/raid/1G bs=1024 count=1048576
  * mitty@raid5:~$ sha1sum -b /var/raid/1G | sudo tee /var/raid/1G.sha1
{{{
c3f03a59a865c1aea6455f8838479614e9225f48 */var/raid/1G
}}}

 * mitty@raid5:~$ df -h /var/raid/
{{{
Filesystem            Size  Used Avail Use% Mounted on
/dev/md0              4.0G  1.1G  3.0G  26% /var/raid
}}}

 == attach new 2 disks ==
 * [[Image(attach7.png,33%)]]

 * mitty@raid5:~$ sudo fdisk -lu /dev/sd?
{{{
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1              63     2097215     1048576+  fd  Linux raid autodetect
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1              63     2097215     1048576+  fd  Linux raid autodetect
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1              63     2097215     1048576+  fd  Linux raid autodetect
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sde1              63     2097215     1048576+  fd  Linux raid autodetect
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sdf1              63     2097215     1048576+  fd  Linux raid autodetect
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sdg1              63     2097215     1048576+  fd  Linux raid autodetect
(snip)
   Device Boot      Start         End      Blocks   Id  System
/dev/sdh1              63     2097215     1048576+  fd  Linux raid autodetect
}}}
 * mitty@raid5:~$ cat /proc/mdstat
{{{
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdc1[1] sdf1[4] sdb1[0] sdd1[2] sde1[3]
      4194048 blocks level 5, 64k chunk, algorithm 2 [5/5] [UUUUU]

unused devices: <none>
}}}
 * mitty@raid5:~$ sudo mdadm -D /dev/md0
{{{
mdadm: metadata format 00.90 unknown, ignored.
/dev/md0:
        Version : 00.90
  Creation Time : Sat Jun  4 20:48:11 2011
     Raid Level : raid5
     Array Size : 4194048 (4.00 GiB 4.29 GB)
  Used Dev Size : 1048512 (1024.11 MiB 1073.68 MB)
   Raid Devices : 5
  Total Devices : 5
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sat Jun  4 21:24:55 2011
          State : clean
 Active Devices : 5
Working Devices : 5
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : b49fdd73:9af2093f:0dfb77a3:1c88c57c (local to host raid5)
         Events : 0.40

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       81        4      active sync   /dev/sdf1
}}}

 === add 1 of 2 disk2 ===
 * mitty@raid5:~$ sudo mdadm /dev/md0 -a /dev/sdg1
{{{
mdadm: metadata format 00.90 unknown, ignored.
mdadm: added /dev/sdg1
}}}
 * mitty@raid5:~$ cat /proc/mdstat
{{{
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdg1[5](S) sdc1[1] sdf1[4] sdb1[0] sdd1[2] sde1[3]
      4194048 blocks level 5, 64k chunk, algorithm 2 [5/5] [UUUUU]

unused devices: <none>
}}}
 * mitty@raid5:~$ sudo mdadm -D /dev/md0
{{{
mdadm: metadata format 00.90 unknown, ignored.
/dev/md0:
        Version : 00.90
  Creation Time : Sat Jun  4 20:48:11 2011
     Raid Level : raid5
     Array Size : 4194048 (4.00 GiB 4.29 GB)
  Used Dev Size : 1048512 (1024.11 MiB 1073.68 MB)
   Raid Devices : 5
  Total Devices : 6
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sat Jun  4 21:36:40 2011
          State : clean
 Active Devices : 5
Working Devices : 6
 Failed Devices : 0
  Spare Devices : 1

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : b49fdd73:9af2093f:0dfb77a3:1c88c57c (local to host raid5)
         Events : 0.42

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       81        4      active sync   /dev/sdf1

       5       8       97        -      spare   /dev/sdg1
}}}

 === add 2 of 2 disks ===
 * mitty@raid5:~$ sudo mdadm /dev/md0 -a /dev/sdh1
{{{
mdadm: metadata format 00.90 unknown, ignored.
mdadm: added /dev/sdh1
}}}
 * mitty@raid5:~$ cat /proc/mdstat
{{{
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdh1[5](S) sdg1[6](S) sdc1[1] sdf1[4] sdb1[0] sdd1[2] sde1[3]
      4194048 blocks level 5, 64k chunk, algorithm 2 [5/5] [UUUUU]

unused devices: <none>
}}}
 * mitty@raid5:~$ sudo mdadm -D /dev/md0
{{{
mdadm: metadata format 00.90 unknown, ignored.
/dev/md0:
        Version : 00.90
  Creation Time : Sat Jun  4 20:48:11 2011
     Raid Level : raid5
     Array Size : 4194048 (4.00 GiB 4.29 GB)
  Used Dev Size : 1048512 (1024.11 MiB 1073.68 MB)
   Raid Devices : 5
  Total Devices : 7
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sat Jun  4 21:37:28 2011
          State : clean
 Active Devices : 5
Working Devices : 7
 Failed Devices : 0
  Spare Devices : 2

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : b49fdd73:9af2093f:0dfb77a3:1c88c57c (local to host raid5)
         Events : 0.44

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       81        4      active sync   /dev/sdf1

       5       8      113        -      spare   /dev/sdh1
       6       8       97        -      spare   /dev/sdg1
}}}

 == grow array ==
 === cannot make RAID5 to RAID6 ===
 * RAID5に後からディスクを追加してRAID6にする機能は(現在は)実装されていない模様

 * mitty@raid5:~$ sudo mdadm --grow /dev/md0 -l6 -n7
{{{
mdadm: metadata format 00.90 unknown, ignored.
mdadm: Need to backup 1280K of critical section..
mdadm: Cannot set device size/shape for /dev/md0: Invalid argument
}}}

 * mitty@raid5:~$ tail /var/log/kern.log
{{{
Jun  4 21:55:44 raid5 kernel: [ 1842.255232] md: couldn't update array info. -22
}}}
 * mitty@raid5:~$ man mdadm
{{{
(snip)

       -l, --level=
(snip)

              Not yet supported with --grow.
}}}

 === RAID5 5 -> 7 disks ===
 * mitty@raid5:~$ sudo mdadm --grow /dev/md0 -n7
{{{
mdadm: metadata format 00.90 unknown, ignored.
mdadm: Need to backup 768K of critical section..
mdadm: ... critical section passed.
}}}

 * mitty@raid5:~$ cat /proc/mdstat
{{{
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdh1[5] sdg1[6] sdc1[1] sdf1[4] sdb1[0] sdd1[2] sde1[3]
      4194048 blocks super 0.91 level 5, 64k chunk, algorithm 2 [7/7] [UUUUUUU]
      [>....................]  reshape =  0.3% (4160/1048512) finish=25.0min speed=693K/sec

unused devices: <none>
}}}
 * mitty@raid5:~$ sudo mdadm -D /dev/md0
{{{
mdadm: metadata format 00.90 unknown, ignored.
/dev/md0:
        Version : 00.91
  Creation Time : Sat Jun  4 20:48:11 2011
     Raid Level : raid5
     Array Size : 4194048 (4.00 GiB 4.29 GB)
  Used Dev Size : 1048512 (1024.11 MiB 1073.68 MB)
   Raid Devices : 7
  Total Devices : 7
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sat Jun  4 21:56:24 2011
          State : clean, recovering
 Active Devices : 7
Working Devices : 7
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

 Reshape Status : 2% complete
  Delta Devices : 2, (5->7)

           UUID : b49fdd73:9af2093f:0dfb77a3:1c88c57c (local to host raid5)
         Events : 0.74

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       81        4      active sync   /dev/sdf1
       5       8      113        5      active sync   /dev/sdh1
       6       8       97        6      active sync   /dev/sdg1
}}}
 * mitty@raid5:~$ tail /var/log/kern.log
{{{
Jun  4 21:55:59 raid5 kernel: [ 1857.490635] RAID5 conf printout:
Jun  4 21:55:59 raid5 kernel: [ 1857.490640]  --- rd:7 wd:7
Jun  4 21:55:59 raid5 kernel: [ 1857.490642]  disk 0, o:1, dev:sdb1
Jun  4 21:55:59 raid5 kernel: [ 1857.490644]  disk 1, o:1, dev:sdc1
Jun  4 21:55:59 raid5 kernel: [ 1857.490646]  disk 2, o:1, dev:sdd1
Jun  4 21:55:59 raid5 kernel: [ 1857.490648]  disk 3, o:1, dev:sde1
Jun  4 21:55:59 raid5 kernel: [ 1857.490650]  disk 4, o:1, dev:sdf1
Jun  4 21:55:59 raid5 kernel: [ 1857.490652]  disk 5, o:1, dev:sdh1
Jun  4 21:55:59 raid5 kernel: [ 1857.490665] RAID5 conf printout:
Jun  4 21:55:59 raid5 kernel: [ 1857.490666]  --- rd:7 wd:7
Jun  4 21:55:59 raid5 kernel: [ 1857.490668]  disk 0, o:1, dev:sdb1
Jun  4 21:55:59 raid5 kernel: [ 1857.490670]  disk 1, o:1, dev:sdc1
Jun  4 21:55:59 raid5 kernel: [ 1857.490672]  disk 2, o:1, dev:sdd1
Jun  4 21:55:59 raid5 kernel: [ 1857.490674]  disk 3, o:1, dev:sde1
Jun  4 21:55:59 raid5 kernel: [ 1857.490675]  disk 4, o:1, dev:sdf1
Jun  4 21:55:59 raid5 kernel: [ 1857.490677]  disk 5, o:1, dev:sdh1
Jun  4 21:55:59 raid5 kernel: [ 1857.490679]  disk 6, o:1, dev:sdg1
Jun  4 21:55:59 raid5 kernel: [ 1857.491421] md: reshape of RAID array md0
Jun  4 21:55:59 raid5 kernel: [ 1857.491428] md: minimum _guaranteed_  speed: 1000 KB/sec/disk.
Jun  4 21:55:59 raid5 kernel: [ 1857.491431] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for reshape.
Jun  4 21:55:59 raid5 kernel: [ 1857.491443] md: using 128k window, over a total of 1048512 blocks.
}}}

 ==== reshape done ====
 * mitty@raid5:~$ tail /var/log/kern.log
{{{
Jun  4 22:01:26 raid5 kernel: [ 2184.441331] md: md0: reshape done.
Jun  4 22:01:26 raid5 kernel: [ 2184.448127] RAID5 conf printout:
Jun  4 22:01:26 raid5 kernel: [ 2184.448130]  --- rd:7 wd:7
Jun  4 22:01:26 raid5 kernel: [ 2184.448132]  disk 0, o:1, dev:sdb1
Jun  4 22:01:26 raid5 kernel: [ 2184.448134]  disk 1, o:1, dev:sdc1
Jun  4 22:01:26 raid5 kernel: [ 2184.448136]  disk 2, o:1, dev:sdd1
Jun  4 22:01:26 raid5 kernel: [ 2184.448138]  disk 3, o:1, dev:sde1
Jun  4 22:01:26 raid5 kernel: [ 2184.448140]  disk 4, o:1, dev:sdf1
Jun  4 22:01:26 raid5 kernel: [ 2184.448141]  disk 5, o:1, dev:sdh1
Jun  4 22:01:26 raid5 kernel: [ 2184.448143]  disk 6, o:1, dev:sdg1
Jun  4 22:01:26 raid5 kernel: [ 2184.448154] md0: detected capacity change from 4294705152 to 6442057728
Jun  4 22:01:26 raid5 kernel: [ 2184.489608] VFS: busy inodes on changed media or resized disk md0
}}}
 * mitty@raid5:~$ cat /proc/mdstat
{{{
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdh1[5] sdg1[6] sdc1[1] sdf1[4] sdb1[0] sdd1[2] sde1[3]
      6291072 blocks level 5, 64k chunk, algorithm 2 [7/7] [UUUUUUU]

unused devices: <none>
}}}
 * mitty@raid5:~$ sudo mdadm -D /dev/md0
{{{
mdadm: metadata format 00.90 unknown, ignored.
/dev/md0:
        Version : 00.90
  Creation Time : Sat Jun  4 20:48:11 2011
     Raid Level : raid5
     Array Size : 6291072 (6.00 GiB 6.44 GB)
  Used Dev Size : 1048512 (1024.11 MiB 1073.68 MB)
   Raid Devices : 7
  Total Devices : 7
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sat Jun  4 22:02:10 2011
          State : active
 Active Devices : 7
Working Devices : 7
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : b49fdd73:9af2093f:0dfb77a3:1c88c57c (local to host raid5)
         Events : 0.137

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       81        4      active sync   /dev/sdf1
       5       8      113        5      active sync   /dev/sdh1
       6       8       97        6      active sync   /dev/sdg1
}}}

 == xfs_growfs ==
 * see also wiki:TipAndDoc/filesystem/xfs_growfs

 * mitty@raid5:~$ df -h /var/raid/
{{{
Filesystem            Size  Used Avail Use% Mounted on
/dev/md0              4.0G  1.1G  3.0G  26% /var/raid
}}}
 * mitty@raid5:~$ mount
{{{
/dev/md0 on /var/raid type xfs (rw)
}}}

 * mitty@raid5:~$ sudo xfs_growfs /var/raid/
{{{
meta-data=/dev/md0               isize=256    agcount=8, agsize=131056 blks
         =                       sectsz=4096  attr=2
data     =                       bsize=4096   blocks=1048448, imaxpct=25
         =                       sunit=16     swidth=64 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal               bsize=4096   blocks=2560, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 1048448 to 1572768
}}}

 * mitty@raid5:~$ df -h /var/raid/
{{{
Filesystem            Size  Used Avail Use% Mounted on
/dev/md0              6.0G  1.1G  5.0G  17% /var/raid
}}}

 == check data ==
 * mitty@raid5:~$ sha1sum -c /var/raid/1G.sha1
{{{
/var/raid/1G: OK
}}}

 * mitty@raid5:~$ sudo mdadm -Ds
{{{
mdadm: metadata format 00.90 unknown, ignored.
ARRAY /dev/md0 level=raid5 num-devices=7 metadata=00.90 UUID=b49fdd73:9af2093f:0dfb77a3:1c88c57c
}}}

 = 7 -> 14 disks =
 * 任意の数だけgrow出来る模様
 * [[Image(attach14.png,33%)]]

 * mitty@raid5:~$ cat /proc/mdstat
{{{
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdf1[4] sdg1[6] sdd1[2] sdh1[5] sde1[3] sdc1[1] sdb1[0]
      6291072 blocks level 5, 64k chunk, algorithm 2 [7/7] [UUUUUUU]

unused devices: <none>
}}}

 == add disks ==
 * mitty@raid5:~$ sudo mdadm /dev/md0 -a /dev/sd[ijklmno]1
{{{
mdadm: metadata format 00.90 unknown, ignored.
mdadm: added /dev/sdi1
mdadm: added /dev/sdj1
mdadm: added /dev/sdk1
mdadm: added /dev/sdl1
mdadm: added /dev/sdm1
mdadm: added /dev/sdn1
mdadm: added /dev/sdo1
}}}

 * mitty@raid5:~$ cat /proc/mdstat
{{{
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdo1[7](S) sdn1[8](S) sdm1[9](S) sdl1[10](S) sdk1[11](S) sdj1[12](S) sdi1[13](S) sdf1[4] sdg1[6] sdd1[2] sdh1[5] sde1[3] sdc1[1] sdb1[0]
      6291072 blocks level 5, 64k chunk, algorithm 2 [7/7] [UUUUUUU]

unused devices: <none>
}}}
 * mitty@raid5:~$ sudo mdadm -D /dev/md0
{{{
mdadm: metadata format 00.90 unknown, ignored.
/dev/md0:
        Version : 00.90
  Creation Time : Sat Jun  4 20:48:11 2011
     Raid Level : raid5
     Array Size : 6291072 (6.00 GiB 6.44 GB)
  Used Dev Size : 1048512 (1024.11 MiB 1073.68 MB)
   Raid Devices : 7
  Total Devices : 14
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sun Jun  5 09:14:36 2011
          State : clean
 Active Devices : 7
Working Devices : 14
 Failed Devices : 0
  Spare Devices : 7

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : b49fdd73:9af2093f:0dfb77a3:1c88c57c (local to host raid5)
         Events : 0.150

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       81        4      active sync   /dev/sdf1
       5       8      113        5      active sync   /dev/sdh1
       6       8       97        6      active sync   /dev/sdg1

       7       8      225        -      spare   /dev/sdo1
       8       8      209        -      spare   /dev/sdn1
       9       8      193        -      spare   /dev/sdm1
      10       8      177        -      spare   /dev/sdl1
      11       8      161        -      spare   /dev/sdk1
      12       8      145        -      spare   /dev/sdj1
      13       8      129        -      spare   /dev/sdi1
}}}

 == grow array ==
 * mitty@raid5:~$ sudo mdadm --grow /dev/md0 -n14
{{{
mdadm: metadata format 00.90 unknown, ignored.
mdadm: Need to backup 832K of critical section..
mdadm: ... critical section passed.
}}}

 * mitty@raid5:~$ sudo mdadm -D /dev/md0
{{{
mdadm: metadata format 00.90 unknown, ignored.
/dev/md0:
        Version : 00.91
  Creation Time : Sat Jun  4 20:48:11 2011
     Raid Level : raid5
     Array Size : 6291072 (6.00 GiB 6.44 GB)
  Used Dev Size : 1048512 (1024.11 MiB 1073.68 MB)
   Raid Devices : 14
  Total Devices : 14
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sun Jun  5 09:16:21 2011
          State : clean, recovering
 Active Devices : 14
Working Devices : 14
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

 Reshape Status : 0% complete
  Delta Devices : 7, (7->14)

           UUID : b49fdd73:9af2093f:0dfb77a3:1c88c57c (local to host raid5)
         Events : 0.164

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       81        4      active sync   /dev/sdf1
       5       8      113        5      active sync   /dev/sdh1
       6       8       97        6      active sync   /dev/sdg1
       7       8      225        7      active sync   /dev/sdo1
       8       8      209        8      active sync   /dev/sdn1
       9       8      193        9      active sync   /dev/sdm1
      10       8      177       10      active sync   /dev/sdl1
      11       8      161       11      active sync   /dev/sdk1
      12       8      145       12      active sync   /dev/sdj1
      13       8      129       13      active sync   /dev/sdi1
}}}
 * mitty@raid5:~$ cat /proc/mdstat
{{{
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdo1[7] sdn1[8] sdm1[9] sdl1[10] sdk1[11] sdj1[12] sdi1[13] sdf1[4] sdg1[6] sdd1[2] sdh1[5] sde1[3] sdc1[1] sdb1[0]
      6291072 blocks super 0.91 level 5, 64k chunk, algorithm 2 [14/14] [UUUUUUUUUUUUUU]
      [>....................]  reshape =  0.6% (7068/1048512) finish=44.1min speed=392K/sec

unused devices: <none>
}}}

 * [[Image(access14.png,33%)]]

 == reshape done ==
 * mitty@raid5:~$ cat /proc/mdstat
{{{
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdo1[7] sdn1[8] sdm1[9] sdl1[10] sdk1[11] sdj1[12] sdi1[13] sdf1[4] sdg1[6] sdd1[2] sdh1[5] sde1[3] sdc1[1] sdb1[0]
      13630656 blocks level 5, 64k chunk, algorithm 2 [14/14] [UUUUUUUUUUUUUU]

unused devices: <none>
}}}
 * mitty@raid5:~$ sudo mdadm -D /dev/md0
{{{
mdadm: metadata format 00.90 unknown, ignored.
/dev/md0:
        Version : 00.90
  Creation Time : Sat Jun  4 20:48:11 2011
     Raid Level : raid5
     Array Size : 13630656 (13.00 GiB 13.96 GB)
  Used Dev Size : 1048512 (1024.11 MiB 1073.68 MB)
   Raid Devices : 14
  Total Devices : 14
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sun Jun  5 09:21:17 2011
          State : clean
 Active Devices : 14
Working Devices : 14
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : b49fdd73:9af2093f:0dfb77a3:1c88c57c (local to host raid5)
         Events : 0.226

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       81        4      active sync   /dev/sdf1
       5       8      113        5      active sync   /dev/sdh1
       6       8       97        6      active sync   /dev/sdg1
       7       8      225        7      active sync   /dev/sdo1
       8       8      209        8      active sync   /dev/sdn1
       9       8      193        9      active sync   /dev/sdm1
      10       8      177       10      active sync   /dev/sdl1
      11       8      161       11      active sync   /dev/sdk1
      12       8      145       12      active sync   /dev/sdj1
      13       8      129       13      active sync   /dev/sdi1

}}}

 == xfs_growfs ==
 * mitty@raid5:~$ sudo xfs_growfs /var/raid/
{{{
xfs_growfs: /var/raid/ is not a mounted XFS filesystem
}}}
  * read-onlyでも良いので、mountが必要

 * mitty@raid5:~$ sudo mount -r /dev/md0 /var/raid/
 * mitty@raid5:~$ sudo xfs_growfs /var/raid/
{{{
meta-data=/dev/md0               isize=256    agcount=13, agsize=131056 blks
         =                       sectsz=4096  attr=2
data     =                       bsize=4096   blocks=1572768, imaxpct=25
         =                       sunit=16     swidth=64 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal               bsize=4096   blocks=2560, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 1572768 to 3407664
}}}

 * mitty@raid5:~$ mount
{{{
/dev/md0 on /var/raid type xfs (ro)
}}}
 * mitty@raid5:~$ df -h /var/raid/
{{{
Filesystem            Size  Used Avail Use% Mounted on
/dev/md0               13G  1.1G   12G   8% /var/raid
}}}


 = misc =
 * reshape中に再起動した場合、arrayの先頭からreshapeが再開される
  * $ dmesg
{{{
[   14.359376] raid5: reshape will continue
(snip)
[   14.361290] ...ok start reshape thread
}}}