我有一个运行 RAID 5 4 驱动器的 Asustor NAS，在系统更新后它重新启动到 Web 控制台中的初始化页面，我认为这是升级过程的一部分所以我开始初始化进程，几分钟后我觉得不对劲并且拔掉电源，NAS 启动到一个干净的操作系统，所有设置都已经消失，无法挂载 RAID。
在终端中检查 mdadm 和 fdisk 后，我发现最后 2 个驱动器已重新初始化为 RAID 0 阵列（sdc4、sdd4）。
我曾尝试组装原始 RAID 但没有成功
# mdadm --assemble /dev/mdx /dev/sd*4
mdadm: superblock on /dev/sdc4 doesn't match others - assembly aborted
mdadm --examine /dev/sd*
这是原始 RAID的结果应该是 [sda4,sdb4, sdc4 , sdd4 ] UUID: 1ba5dfd1:e861b791:eb307ef1:4ae4e4ad 8T。
意外创建的 raid0 是 [ sdc4 , sdd4 ] UUID: 06b57325:241ba722:6dd303af:baaa5e4e
/dev/sda:
MBR Magic : aa55
Partition[0] : 522240 sectors at 2048 (type 83)
Partition[3] : 2047 sectors at 1 (type ee)
mdadm: No md superblock detected on /dev/sda1.
/dev/sda2:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 1c90030d:10445d9f:d39fc32a:06d4b79a
Name : AS1004T-7CBC:0 (local to host AS1004T-7CBC)
Creation Time : Sun Jun 11 10:56:28 2017
Raid Level : raid1
Raid Devices : 4
Avail Dev Size : 4190208 (2046.34 MiB 2145.39 MB)
Array Size : 2095104 (2046.34 MiB 2145.39 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4008 sectors, after=0 sectors
State : active
Device UUID : cca1545a:14112668:0ebd0ed3:df55018d
Update Time : Sun Oct 13 01:05:27 2019
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 95866108 - correct
Events : 228987
Device Role : Active device 3
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sda3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 8c3ca866:3e6b6804:32f2955e:1b955d76
Name : AS1004T-7CBC:126 (local to host AS1004T-7CBC)
Creation Time : Sun May 14 09:50:45 2023
Raid Level : raid1
Raid Devices : 4
Avail Dev Size : 4190208 (2046.34 MiB 2145.39 MB)
Array Size : 2095104 (2046.34 MiB 2145.39 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4008 sectors, after=0 sectors
State : clean
Device UUID : f3836318:4899a170:a0018b8b:1aa428ab
Update Time : Sun May 14 14:40:28 2023
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 48f1cfbb - correct
Events : 92
Device Role : Active device 3
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sda4:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 1ba5dfd1:e861b791:eb307ef1:4ae4e4ad
Name : AS1004T-7CBC:1 (local to host AS1004T-7CBC)
Creation Time : Sun Jun 11 10:56:51 2017
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 5851357184 (2790.14 GiB 2995.89 GB)
Array Size : 8777035776 (8370.43 GiB 8987.68 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=0 sectors
State : clean
Device UUID : 6a18260d:f0d1b882:5608a7e4:8eeabe1f
Update Time : Sun May 14 09:31:25 2023
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 6e46beec - correct
Events : 213501
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 3
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdb:
MBR Magic : aa55
Partition[0] : 522240 sectors at 2048 (type 83)
Partition[3] : 2047 sectors at 1 (type ee)
mdadm: No md superblock detected on /dev/sdb1.
/dev/sdb2:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 1c90030d:10445d9f:d39fc32a:06d4b79a
Name : AS1004T-7CBC:0 (local to host AS1004T-7CBC)
Creation Time : Sun Jun 11 10:56:28 2017
Raid Level : raid1
Raid Devices : 4
Avail Dev Size : 4190208 (2046.34 MiB 2145.39 MB)
Array Size : 2095104 (2046.34 MiB 2145.39 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4008 sectors, after=0 sectors
State : active
Device UUID : 648f0d6d:967f432c:3b9e1ceb:d15959c2
Update Time : Sun Oct 13 01:05:27 2019
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : b9c2a23f - correct
Events : 228987
Device Role : Active device 1
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdb3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 8c3ca866:3e6b6804:32f2955e:1b955d76
Name : AS1004T-7CBC:126 (local to host AS1004T-7CBC)
Creation Time : Sun May 14 09:50:45 2023
Raid Level : raid1
Raid Devices : 4
Avail Dev Size : 4190208 (2046.34 MiB 2145.39 MB)
Array Size : 2095104 (2046.34 MiB 2145.39 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4008 sectors, after=0 sectors
State : clean
Device UUID : 8adc82c0:010edc11:5702a9f6:7287da86
Update Time : Sun May 14 14:40:28 2023
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : d91b8119 - correct
Events : 92
Device Role : Active device 2
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdb4:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 1ba5dfd1:e861b791:eb307ef1:4ae4e4ad
Name : AS1004T-7CBC:1 (local to host AS1004T-7CBC)
Creation Time : Sun Jun 11 10:56:51 2017
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 5851357184 (2790.14 GiB 2995.89 GB)
Array Size : 8777035776 (8370.43 GiB 8987.68 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=0 sectors
State : clean
Device UUID : 15bd0bdb:b5fdcfaf:94729f61:ed9e7bea
Update Time : Sun May 14 09:31:25 2023
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : b0f8adf8 - correct
Events : 213501
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 1
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdc:
MBR Magic : aa55
Partition[0] : 522240 sectors at 2048 (type 83)
Partition[3] : 2047 sectors at 1 (type ee)
mdadm: No md superblock detected on /dev/sdc1.
/dev/sdc2:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 14d010c5:aaed7a5c:30956792:cfd0c452
Name : AS1004T-7CBC:0 (local to host AS1004T-7CBC)
Creation Time : Sun May 14 09:50:35 2023
Raid Level : raid1
Raid Devices : 4
Avail Dev Size : 4190208 (2046.34 MiB 2145.39 MB)
Array Size : 2095104 (2046.34 MiB 2145.39 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4008 sectors, after=0 sectors
State : clean
Device UUID : 373358f6:76ca625d:e9193081:216676cb
Update Time : Sun May 14 14:37:42 2023
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : ba188081 - correct
Events : 880
Device Role : Active device 1
Array State : AA.. ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdc3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 8c3ca866:3e6b6804:32f2955e:1b955d76
Name : AS1004T-7CBC:126 (local to host AS1004T-7CBC)
Creation Time : Sun May 14 09:50:45 2023
Raid Level : raid1
Raid Devices : 4
Avail Dev Size : 4190208 (2046.34 MiB 2145.39 MB)
Array Size : 2095104 (2046.34 MiB 2145.39 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4008 sectors, after=0 sectors
State : clean
Device UUID : 737541e2:f5a3673d:8db35b12:2db86324
Update Time : Sun May 14 14:40:28 2023
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : dfa191e3 - correct
Events : 92
Device Role : Active device 1
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdc4:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 06b57325:241ba722:6dd303af:baaa5e4e
Name : AS1004T-7CBC:1 (local to host AS1004T-7CBC)
Creation Time : Sun May 14 09:51:00 2023
Raid Level : raid0
Raid Devices : 2
Avail Dev Size : 5851357184 (2790.14 GiB 2995.89 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=0 sectors
State : clean
Device UUID : d73a946c:9aa8e26e:c4388d7a:566dcf90
Update Time : Sun May 14 09:51:00 2023
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 9bd7221c - correct
Events : 0
Chunk Size : 64K
Device Role : Active device 1
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd:
MBR Magic : aa55
Partition[0] : 522240 sectors at 2048 (type 83)
Partition[3] : 2047 sectors at 1 (type ee)
mdadm: No md superblock detected on /dev/sdd1.
/dev/sdd2:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 14d010c5:aaed7a5c:30956792:cfd0c452
Name : AS1004T-7CBC:0 (local to host AS1004T-7CBC)
Creation Time : Sun May 14 09:50:35 2023
Raid Level : raid1
Raid Devices : 4
Avail Dev Size : 4190208 (2046.34 MiB 2145.39 MB)
Array Size : 2095104 (2046.34 MiB 2145.39 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4008 sectors, after=0 sectors
State : clean
Device UUID : acfa8c63:b226e810:3640a42a:9f8b72b1
Update Time : Sun May 14 14:37:42 2023
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 6a42effb - correct
Events : 880
Device Role : Active device 0
Array State : AA.. ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 8c3ca866:3e6b6804:32f2955e:1b955d76
Name : AS1004T-7CBC:126 (local to host AS1004T-7CBC)
Creation Time : Sun May 14 09:50:45 2023
Raid Level : raid1
Raid Devices : 4
Avail Dev Size : 4190208 (2046.34 MiB 2145.39 MB)
Array Size : 2095104 (2046.34 MiB 2145.39 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4008 sectors, after=0 sectors
State : clean
Device UUID : 1dd56ce1:770fa0d6:13127388:46c0d14f
Update Time : Sun May 14 14:40:28 2023
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 198ac3af - correct
Events : 92
Device Role : Active device 0
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd4:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 06b57325:241ba722:6dd303af:baaa5e4e
Name : AS1004T-7CBC:1 (local to host AS1004T-7CBC)
Creation Time : Sun May 14 09:51:00 2023
Raid Level : raid0
Raid Devices : 2
Avail Dev Size : 7804860416 (3721.65 GiB 3996.09 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=0 sectors
State : clean
Device UUID : 1dece618:58743ad6:9f56922c:fa500120
Update Time : Sun May 14 09:51:00 2023
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 6528b89e - correct
Events : 0
Chunk Size : 64K
Device Role : Active device 0
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
我有以下问题：
- RAID 0 阵列的重新初始化是否覆盖了我的数据？
- 我应该只对第 3 个驱动器进行零超级阻塞并重新组装前 3 个驱动器吗？
- 由于前 2 个驱动器看起来不错，我可以从前 2 个驱动器恢复后 2 个驱动器的超级块吗？
- 我想恢复 RAID 5 数据
我做了一个实验来检查 mdadm --create 是否在创建的数组上销毁（多少）数据，幸运的是不多。
root@osboxes:/home/osboxes# mdadm --create --verbose /dev/md0 --level=5 --raid-devices=4 /dev/sd{b,c,d,e}
mdadm: layout defaults to left-symmetric
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 512K
mdadm: size set to 100352K
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
root@osboxes:/home/osboxes# mkfs.ext4 /dev/md0
mke2fs 1.46.2 (28-Feb-2021)
Creating filesystem with 301056 1k blocks and 75480 inodes
Filesystem UUID: 9f536c05-4178-4aa3-8b1a-c96f3c34de4e
Superblock backups stored on blocks:
8193, 24577, 40961, 57345, 73729, 204801, 221185
Allocating group tables: done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done
root@osboxes:/home/osboxes# mount /dev/md0 /mnt/
root@osboxes:/home/osboxes# dd if=/dev/urandom of=/mnt/test count=200000
200000+0 records in
200000+0 records out
102400000 bytes (102 MB, 98 MiB) copied, 0.860987 s, 119 MB/s
root@osboxes:/home/osboxes# md5sum /mnt/test
5b6024b89c0facb25bfb3055b21c4042 /mnt/test
root@osboxes:/home/osboxes# umount /mnt/
root@osboxes:/home/osboxes# mdadm --stop md0
mdadm: stopped md0
root@osboxes:/home/osboxes# mdadm --create --verbose /dev/md0 --level=0 --raid-devices=2 /dev/sd{d,e} # the command finish instantly I dont think it have time to write 100MB data
mdadm: chunk size defaults to 512K
mdadm: /dev/sdd appears to be part of a raid array:
level=raid5 devices=4 ctime=Mon May 15 02:53:07 2023
mdadm: /dev/sde appears to be part of a raid array:
level=raid5 devices=4 ctime=Mon May 15 02:53:07 2023
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
root@osboxes:/home/osboxes# mdadm --assemble --force /dev/md0 /dev/sd{b,c,d,e}
mdadm: /dev/sdd is busy - skipping
mdadm: /dev/sde is busy - skipping
mdadm: Fail create md0 when using /sys/module/md_mod/parameters/new_array
mdadm: /dev/md0 is already in use.
root@osboxes:/home/osboxes# mdadm --stop md0
mdadm: stopped md0
root@osboxes:/home/osboxes# mdadm --assemble --force /dev/md0 /dev/sd{b,c,d,e}
mdadm: superblock on /dev/sdd doesn't match others - assembly aborted
root@osboxes:/home/osboxes# mdadm --create /dev/md126 --assume-clean --raid-devices=4 --level=5 /dev/sd{b,c,d,e}
mdadm: /dev/sdb appears to be part of a raid array:
level=raid5 devices=4 ctime=Mon May 15 02:53:07 2023
mdadm: /dev/sdc appears to be part of a raid array:
level=raid5 devices=4 ctime=Mon May 15 02:53:07 2023
mdadm: /dev/sdd appears to be part of a raid array:
level=raid0 devices=2 ctime=Mon May 15 02:55:14 2023
mdadm: /dev/sde appears to be part of a raid array:
level=raid0 devices=2 ctime=Mon May 15 02:55:14 2023
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md126 started.
root@osboxes:/home/osboxes# mount /dev/md126 /mnt
root@osboxes:/home/osboxes# md5sum /mnt/
lost+found/ test
root@osboxes:/home/osboxes# md5sum /mnt/test
5b6024b89c0facb25bfb3055b21c4042 /mnt/test
但如果我创建文件系统并将文件写入新阵列，恢复阵列将损坏，但仍然可读。
root@osboxes:/home/osboxes# umount /mnt/
root@osboxes:/home/osboxes# mdadm --stop md126
mdadm: stopped md126
root@osboxes:/home/osboxes# mdadm --create --verbose /dev/md0 --level=0 --raid-devices=2 /dev/sd{d,e}
mdadm: chunk size defaults to 512K
mdadm: /dev/sdd appears to be part of a raid array:
level=raid5 devices=4 ctime=Mon May 15 02:57:09 2023
mdadm: /dev/sde appears to be part of a raid array:
level=raid5 devices=4 ctime=Mon May 15 02:57:09 2023
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
root@osboxes:/home/osboxes# mdadm --assemble --force /dev/md0 /dev/sd{b,c,d,e} ^C
root@osboxes:/home/osboxes# mkfs.ext4 /dev/md0
mke2fs 1.46.2 (28-Feb-2021)
Creating filesystem with 200704 1k blocks and 50200 inodes
Filesystem UUID: c1ded6ea-d212-473a-a282-7c3dd4f6777e
Superblock backups stored on blocks:
8193, 24577, 40961, 57345, 73729
Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done
root@osboxes:/home/osboxes# mount /dev/md0 /mnt/
root@osboxes:/home/osboxes# ls /mnt/
lost+found
root@osboxes:/home/osboxes# echo test>/mnt/test
root@osboxes:/home/osboxes# umount /mnt/
root@osboxes:/home/osboxes# mdadm --stop md0
mdadm: stopped md0
root@osboxes:/home/osboxes# mdadm --create /dev/md126 --assume-clean --raid-devices=4 --level=5 /dev/sd{b,c,d,e}
mdadm: /dev/sdb appears to be part of a raid array:
level=raid5 devices=4 ctime=Mon May 15 02:57:09 2023
mdadm: /dev/sdc appears to be part of a raid array:
level=raid5 devices=4 ctime=Mon May 15 02:57:09 2023
mdadm: /dev/sdd appears to be part of a raid array:
level=raid0 devices=2 ctime=Mon May 15 03:01:55 2023
mdadm: /dev/sde appears to be part of a raid array:
level=raid0 devices=2 ctime=Mon May 15 03:01:55 2023
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md126 started.
root@osboxes:/home/osboxes# mount /dev/md126 /mnt/
root@osboxes:/home/osboxes# ls /mnt/
lost+found test
root@osboxes:/home/osboxes# md5sum /mnt/test
4d389d72a1db56e9d73cbe753fabf595 /mnt/test