Linux 用指令檢查 RAID 狀態

先看看 RAID 狀態

[root@liho ~]# mdadm --detail-platform
       Platform : Intel(R) Rapid Storage Technology enterprise
        Version : 4.5.0.1012
    RAID Levels : raid0 raid1 raid10 raid5
    Chunk Sizes : 4k 8k 16k 32k 64k 128k
    2TB volumes : supported
      2TB disks : supported
      Max Disks : 8
    Max Volumes : 2 per array, 4 per controller
 I/O Controller : /sys/devices/pci0000:00/0000:00:1f.2 (SATA)
          Port0 : /dev/sda (P02724108934)
          Port1 : /dev/sdb (P02724108469)
          Port2 : /dev/sdc (BTYS834502XJ3P8EGN)
          Port3 : /dev/sdd (H567360418)
          Port4 : - no device attached -
          Port5 : - no device attached -

正常沒問題的狀態會是下面這樣：看到 md126 的 [UU] 就是代表沒問題（”U” 代表 UP）。

[root@liho ~]# cat /proc/mdstat
Personalities : [raid1]
md125 : inactive sdd[0](S)
      1105 blocks super external:imsm

md126 : active raid1 sda[1] sdb[0]
      475109376 blocks super external:/md127/0 [2/2] [UU]

md127 : inactive sda[1](S) sdb[0](S)
      10402 blocks super external:imsm

unused devices: <none>

在狀態沒問題的時候 可以看到兩個 “active sync”

[root@liho ~]# mdadm -D /dev/md126
/dev/md126:
         Container : /dev/md/imsm0, member 0
        Raid Level : raid1
        Array Size : 475109376 (453.10 GiB 486.51 GB)
     Used Dev Size : 475109376 (453.10 GiB 486.51 GB)
      Raid Devices : 2
     Total Devices : 2

             State : clean
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : resync


              UUID : 270c570c:a49daf9b:c0e14b6c:e4a6b30e
    Number   Major   Minor   RaidDevice State
       1       8        0        0      active sync   /dev/sda
       0       8       16        1      active sync   /dev/sdb

下面的RAID狀態是正在重新建立中 (rebuild)，看到 md126 的 [U_] 這邊右邊那個碟 「沒有UP」代表有問題。

[root@liho ~]# cat /proc/mdstat
Personalities : [raid1]
md125 : inactive sdd[0](S)
      1105 blocks super external:imsm

md126 : active raid1 sda[1] sdb[0]
      475109376 blocks super external:/md127/0 [2/1] [U_]
      [=======>.............]  recovery = 36.7% (174653440/475109376) finish=29.5min speed=169288K/sec

md127 : inactive sdb[1](S) sda[0](S)
      10402 blocks super external:imsm

unused devices: <none>

然後個別看看 /dev/mdXXX 詳細的資訊，下面是 RAID1：

[root@liho ~]# mdadm -D /dev/md126
/dev/md126:
         Container : /dev/md/imsm0, member 0
        Raid Level : raid1
        Array Size : 475109376 (453.10 GiB 486.51 GB)
     Used Dev Size : 475109376 (453.10 GiB 486.51 GB)
      Raid Devices : 2
     Total Devices : 2

             State : clean, degraded, recovering
    Active Devices : 1
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 1

Consistency Policy : resync

    Rebuild Status : 41% complete


              UUID : 270c570c:a49daf9b:c0e14b6c:e4a6b30e
    Number   Major   Minor   RaidDevice State
       1       8        0        0      active sync   /dev/sda
       0       8       16        1      spare rebuilding   /dev/sdb

下面是 spare 碟：

[root@liho ~]# mdadm -D /dev/md125
/dev/md125:
           Version : imsm
        Raid Level : container
     Total Devices : 1

   Working Devices : 1

     Member Arrays :

    Number   Major   Minor   RaidDevice

       -       8       48        -        /dev/sdd

我不太懂已經有 RAID1 的 md126 為什麼還會有 md127？還是這只是一個 container (容器)?

[root@liho ~]# mdadm -D /dev/md127
/dev/md127:
           Version : imsm
        Raid Level : container
     Total Devices : 2

   Working Devices : 2


              UUID : 7bed3288:d4b81d88:ab300edb:fffee458
     Member Arrays : /dev/md/Volume0

    Number   Major   Minor   RaidDevice

       -       8        0        -        /dev/sda
       -       8       16        -        /dev/sdb

其他資訊：How to add Hot Spare Volume to the existing mdadm software RAID array