如何重新组装 mdadm RAID5 阵列(或从中恢复数据)?

如何重新组装 mdadm RAID5 阵列(或从中恢复数据)?

我正在尝试从故障 NAS 的 RAID5 阵列中恢复所有我能恢复的数据。

磁盘被物理移动到另一台服务器以便进行映像处理,但 Knoppix “有帮助地”在启动时检测并恢复了阵列:-

[  677.791667] md: md0 stopped.
[  677.793443] md: bind<sdb>
[  677.793580] md: bind<sdc>
[  677.793866] md: bind<sdd>
[  677.794004] md: bind<sda>
[  678.671014] md: raid6 personality registered for level 6
[  678.671017] md: raid5 personality registered for level 5
[  678.671019] md: raid4 personality registered for level 4
[  678.671446] md/raid:md0: device sda operational as raid disk 0
[  678.671449] md/raid:md0: device sdc operational as raid disk 2
[  678.671452] md/raid:md0: device sdb operational as raid disk 1
[  678.671840] md/raid:md0: allocated 4222kB
[  678.671874] md/raid:md0: raid level 5 active with 3 out of 4 devices, algorithm 2
[  678.671877] RAID conf printout:
[  678.671879]  --- level:5 rd:4 wd:3
[  678.671881]  disk 0, o:1, dev:sda
[  678.671883]  disk 1, o:1, dev:sdb
[  678.671886]  disk 2, o:1, dev:sdc
[  678.671888]  disk 3, o:1, dev:sdd
[  678.671923] md0: detected capacity change from 0 to 4500901330944
  ^ RAID conf printout repeated
  ^ RAID conf printout repeated
[  678.679071] md: recovery of RAID array md0
[  678.679074] md: minimum _guaranteed_  speed: 1000 KB/sec/disk.
[  678.679077] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for recovery.
[  678.679083] md: using 128k window, over a total of 1465137152 blocks.
[  678.679086] md: resuming recovery of md0 from checkpoint.
[  678.694387]  md0: unknown partition table
[18209.608703] md: md0: recovery done
[18209.690600] RAID conf printout:
[18209.690605]  --- level:5 rd:4 wd:4
[18209.690607]  disk 0, o:1, dev:sda
[18209.690610]  disk 1, o:1, dev:sdb
[18209.690612]  disk 2, o:1, dev:sdc
[18209.690614]  disk 3, o:1, dev:sdd

之后,阵列看起来很健康,/proc/mdstat显示:-

Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sda[0] sdd[4] sdc[2] sdb[1]
      4395411456 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]

但是,我无法/dev/md0直接安装或找到任何逻辑卷。

使用dd提取的前 512 个字节/dev/md0可以得到位于阵列而不是 MBR 上的文件的部分内容,因此我怀疑 这是因为数组的组装顺序是错误的。

如果正确,我该如何重新组装阵列?

如果没有,尝试从阵列中恢复数据的最佳方法是什么?


mdadm -D /dev/md0

/dev/md0:
        Version : 1.2
  Creation Time : Sun Aug  7 17:25:36 2011
     Raid Level : raid5
     Array Size : 4395411456 (4191.79 GiB 4500.90 GB)
  Used Dev Size : 1465137152 (1397.26 GiB 1500.30 GB)
   Raid Devices : 4
  Total Devices : 4
    Persistence : Superblock is persistent

    Update Time : Fri Aug 12 21:54:53 2011
          State : clean
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 512K

           Name : Microknoppix:1  (local to host Microknoppix)
           UUID : 37b79cab:d800da6a:eec72e0d:6547b6ef
         Events : 19

    Number   Major   Minor   RaidDevice State
       0       8        0        0      active sync   /dev/sda
       1       8       16        1      active sync   /dev/sdb
       2       8       32        2      active sync   /dev/sdc
       4       8       48        3      active sync   /dev/sdd

mdadm -E /dev/sd?

/dev/sda:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 37b79cab:d800da6a:eec72e0d:6547b6ef
           Name : Microknoppix:1  (local to host Microknoppix)
  Creation Time : Sun Aug  7 17:25:36 2011
     Raid Level : raid5
   Raid Devices : 4

 Avail Dev Size : 2930275120 (1397.26 GiB 1500.30 GB)
     Array Size : 8790822912 (4191.79 GiB 4500.90 GB)
  Used Dev Size : 2930274304 (1397.26 GiB 1500.30 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : 42c9006b:1405120d:edf4d6da:e707f2dd

    Update Time : Mon Aug 15 02:19:35 2011
       Checksum : 40b694de - correct
         Events : 19

         Layout : left-symmetric
     Chunk Size : 512K

   Device Role : Active device 0
   Array State : AAAA ('A' == active, '.' == missing)
/dev/sdb:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 37b79cab:d800da6a:eec72e0d:6547b6ef
           Name : Microknoppix:1  (local to host Microknoppix)
  Creation Time : Sun Aug  7 17:25:36 2011
     Raid Level : raid5
   Raid Devices : 4

 Avail Dev Size : 2930275120 (1397.26 GiB 1500.30 GB)
     Array Size : 8790822912 (4191.79 GiB 4500.90 GB)
  Used Dev Size : 2930274304 (1397.26 GiB 1500.30 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : 39fc5928:11ecb5b6:c3c088e6:2833b7ea

    Update Time : Mon Aug 15 02:19:35 2011
       Checksum : c02aa5ea - correct
         Events : 19

         Layout : left-symmetric
     Chunk Size : 512K

   Device Role : Active device 1
   Array State : AAAA ('A' == active, '.' == missing)
/dev/sdc:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 37b79cab:d800da6a:eec72e0d:6547b6ef
           Name : Microknoppix:1  (local to host Microknoppix)
  Creation Time : Sun Aug  7 17:25:36 2011
     Raid Level : raid5
   Raid Devices : 4

 Avail Dev Size : 2930275120 (1397.26 GiB 1500.30 GB)
     Array Size : 8790822912 (4191.79 GiB 4500.90 GB)
  Used Dev Size : 2930274304 (1397.26 GiB 1500.30 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : 90c64aa7:82b06090:fe9363e1:380dc0da

    Update Time : Mon Aug 15 02:19:35 2011
       Checksum : 3a9e1ff - correct
         Events : 19

         Layout : left-symmetric
     Chunk Size : 512K

   Device Role : Active device 2
   Array State : AAAA ('A' == active, '.' == missing)
/dev/sdd:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 37b79cab:d800da6a:eec72e0d:6547b6ef
           Name : Microknoppix:1  (local to host Microknoppix)
  Creation Time : Sun Aug  7 17:25:36 2011
     Raid Level : raid5
   Raid Devices : 4

 Avail Dev Size : 2930275120 (1397.26 GiB 1500.30 GB)
     Array Size : 8790822912 (4191.79 GiB 4500.90 GB)
  Used Dev Size : 2930274304 (1397.26 GiB 1500.30 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : fab3ec51:50f9bbc6:7ac51700:54195903

    Update Time : Mon Aug 15 02:19:35 2011
       Checksum : 2bf455cf - correct
         Events : 19

         Layout : left-symmetric
     Chunk Size : 512K

   Device Role : Active device 3
   Array State : AAAA ('A' == active, '.' == missing)

fdisk -l

Disk /dev/sda: 1500.3 GB, 1500301910016 bytes
255 heads, 63 sectors/track, 182401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x894e894e

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1      267350  2147483647+  ee  GPT

Disk /dev/sdb: 1500.3 GB, 1500301910016 bytes
255 heads, 63 sectors/track, 182401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdb doesn't contain a valid partition table

Disk /dev/sdc: 1500.3 GB, 1500301910016 bytes
255 heads, 63 sectors/track, 182401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdc doesn't contain a valid partition table

Disk /dev/sdd: 1500.3 GB, 1500301910016 bytes
255 heads, 63 sectors/track, 182401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdd doesn't contain a valid partition table

Disk /dev/md0: 4500.9 GB, 4500901330944 bytes
2 heads, 4 sectors/track, 1098852864 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 524288 bytes / 1572864 bytes
Disk identifier: 0x312e312f

Disk /dev/md0 doesn't contain a valid partition table

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