我拔掉了 raid 5 的 4 个磁盘中的 2 个的电源插头。从那时起它就无法启动了。即使使用 --run --force、--readwrite 等，我也能很快看到它，因此数据不应该（太多）损坏。
详细信息如下：
/dev/md2:
Version : 1.2
Creation Time : Mon Oct 28 14:46:16 2019
Raid Level : raid5
Used Dev Size : 243138560 (231.88 GiB 248.97 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Thu Apr 9 20:37:49 2020
State : active, FAILED, Not Started
Active Devices : 0
Working Devices : 4
Failed Devices : 0
Spare Devices : 4
Layout : left-symmetric
Chunk Size : 512K
Consistency Policy : unknown
Number Major Minor RaidDevice State
- 0 0 0 removed
- 0 0 1 removed
- 0 0 2 removed
- 0 0 3 removed
- 8 50 3 spare rebuilding /dev/sdd2
- 8 34 1 spare rebuilding /dev/sdc2
- 8 18 2 spare rebuilding /dev/sdb2
- 8 2 0 spare rebuilding /dev/sda2
现在我可以使用 sudo mdadm --create /dev/md2 --level=5 --raid-devices=4 --chunk=512 /dev/sdd2 /dev/sdb2 /dev/sda2 /dev/sdc2 简单地重新创建阵列吗？我应该关心驱动器的顺序，对吗？
根据要求，--examine 的输出：
/dev/sda2:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x8b
Array UUID : 0956b1a2:4ed1052a:016155a1:940db446
Name : raspberrypi3:2
Creation Time : Mon Oct 28 14:46:16 2019
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 486277120 (231.88 GiB 248.97 GB)
Array Size : 729415680 (695.63 GiB 746.92 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Recovery Offset : 36416 sectors
Unused Space : before=262056 sectors, after=0 sectors
State : clean
Device UUID : da9f05d3:64d47a14:78eedb5e:dd69151c
Internal Bitmap : 8 sectors from superblock
Update Time : Thu Apr 9 20:37:49 2020
Bad Block Log : 512 entries available at offset 72 sectors - bad blocks present.
Checksum : ccf72dc4 - correct
Events : 8802
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 0
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdb2:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x8b
Array UUID : 0956b1a2:4ed1052a:016155a1:940db446
Name : raspberrypi3:2
Creation Time : Mon Oct 28 14:46:16 2019
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 486277120 (231.88 GiB 248.97 GB)
Array Size : 729415680 (695.63 GiB 746.92 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Recovery Offset : 36416 sectors
Unused Space : before=262056 sectors, after=0 sectors
State : active
Device UUID : e709a92a:c10f1949:c9868538:f5cc2acc
Internal Bitmap : 8 sectors from superblock
Update Time : Thu Apr 9 20:37:49 2020
Bad Block Log : 512 entries available at offset 72 sectors - bad blocks present.
Checksum : e2f7ce99 - correct
Events : 8802
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 2
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdc2:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x8b
Array UUID : 0956b1a2:4ed1052a:016155a1:940db446
Name : raspberrypi3:2
Creation Time : Mon Oct 28 14:46:16 2019
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 486277120 (231.88 GiB 248.97 GB)
Array Size : 729415680 (695.63 GiB 746.92 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Recovery Offset : 36416 sectors
Unused Space : before=262056 sectors, after=0 sectors
State : active
Device UUID : e1c4f361:af07c81c:1e6b8f72:962869a5
Internal Bitmap : 8 sectors from superblock
Update Time : Thu Apr 9 20:37:49 2020
Bad Block Log : 512 entries available at offset 72 sectors - bad blocks present.
Checksum : 139c176 - correct
Events : 8801
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 1
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd2:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x8b
Array UUID : 0956b1a2:4ed1052a:016155a1:940db446
Name : raspberrypi3:2
Creation Time : Mon Oct 28 14:46:16 2019
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 486277120 (231.88 GiB 248.97 GB)
Array Size : 729415680 (695.63 GiB 746.92 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Recovery Offset : 36416 sectors
Unused Space : before=262056 sectors, after=0 sectors
State : active
Device UUID : ce27edb8:365853c7:e0434b32:5ae01e33
Internal Bitmap : 8 sectors from superblock
Update Time : Thu Apr 9 20:37:49 2020
Bad Block Log : 512 entries available at offset 72 sectors - bad blocks present.
Checksum : 50300573 - correct
Events : 8801
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 3
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
答案1
因此，经过一周的各种尝试，答案是坏块列表。在发生硬故障之前，RAID 阵列开始将所有对底层磁盘的访问添加为坏块。因此，即使通过强制阵列以“echo [X,Y,Z,W] | sudo tee /sys/block/md2/md/dev-sd[a,b,c,d]2/slot”开头来组装磁盘，也会在访问 /dev/mdX 时导致 I/O 错误。
因此，我使用“sudo mdadm --assemble --update=force-no-bbl /dev/md2 /dev/sda2 /dev/sdd2 /dev/sdc2 /dev/sdb2”强制阵列开始忽略阻止列表。疯狂的是，根本找不到原因。我只收到“dev md2 上的缓冲区 I/O 错误，逻辑块 0，异步页面读取”。这导致网络上没有任何结果……