我有两个磁盘（sda 和 sdc，我不知道其他的命运是否有）组装为 RAID-5。几次突然关闭后，其中一名突袭成员变得隐形，我无法重新组装它。我对Linux文件系统包括RAID-5不是很熟悉。据我所知，由于 RAID-5，我不会丢失任何文件，但我不知道我的 sdc 磁盘是否损坏，如果没有损坏，是否可以在不丢失任何信息的情况下重新组装它们，或者如果它坏了我如何访问我的文件。我很感激任何帮助！
$ lsblk -o NAME,SIZE,FSTYPE,TYPE,MOUNTPOINT
NAME SIZE FSTYPE TYPE MOUNTPOINT
loop0 27,1M squashfs loop /snap/snapd/7264
loop1 55M squashfs loop /snap/core18/1705
loop2 240,8M squashfs loop /snap/gnome-3-34-1804/24
loop3 62,1M squashfs loop /snap/gtk-common-themes/1506
loop4 49,8M squashfs loop /snap/snap-store/433
sda 3,7T promise_fasttrack_raid_member disk
└─sda1 3,7T linux_raid_member part
sdb 465,8G disk
├─sdb1 186,4G ext4 part /
├─sdb2 1K part
├─sdb3 268,2G ext4 part /home
└─sdb5 11,2G swap part [SWAP]
和
$sudo parted -l
Model: ATA WDC WD40EZRX-00S (scsi)
Disk /dev/sda: 4001GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 4001GB 4001GB ext4 raid
Model: ATA Samsung SSD 840 (scsi)
Disk /dev/sdb: 500GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 1049kB 200GB 200GB primary ext4 boot
2 200GB 212GB 12,0GB extended
5 200GB 212GB 12,0GB logical linux-swap(v1)
3 212GB 500GB 288GB primary ext4
我只能在 Ubuntu 中的“磁盘”应用程序中看到它，并且它显示 sdc 磁盘“无媒体”。
sda分区似乎是正确的。
我无法重新组装它
sudo mdadm --assemble --scan
升级ubuntu 20时出现以下错误。
grub-probe: warning: disk does not exist, so falling back to partition device /dev/sdc1.
grub-probe: error: cannot read `/dev/sdc1': Input/output error.
更新：
重新启动后它显示了磁盘（我不知道为什么或如何）。但还是无法组装和安装。
$ lsblk -o NAME,SIZE,FSTYPE,TYPE,MOUNTPOINT
NAME SIZE FSTYPE TYPE MOUNTPOINT
loop0 55M squashfs loop /snap/core18/1705
loop1 61,9M squashfs loop /snap/core20/1270
loop2 62,1M squashfs loop /snap/gtk-common-themes/1506
loop3 108,1M squashfs loop /snap/remmina/5130
loop4 49,8M squashfs loop /snap/snap-store/433
loop5 240,8M squashfs loop /snap/gnome-3-34-1804/24
loop6 27,1M squashfs loop /snap/snapd/7264
loop7 247,9M squashfs loop /snap/gnome-3-38-2004/87
loop8 55,5M squashfs loop /snap/core18/2284
loop9 43,4M squashfs loop /snap/snapd/14549
loop10 4K squashfs loop /snap/bare/5
loop11 65,2M squashfs loop /snap/gtk-common-themes/1519
loop12 54,2M squashfs loop /snap/snap-store/558
loop13 219M squashfs loop /snap/gnome-3-34-1804/77
sda 3,7T promise_fasttrack_raid_member disk
└─sda1 3,7T linux_raid_member part
sdb 465,8G disk
├─sdb1 186,4G ext4 part /
├─sdb2 1K part
├─sdb3 268,2G ext4 part /home
└─sdb5 11,2G swap part [SWAP]
sdc 3,7T promise_fasttrack_raid_member disk
└─sdc1 3,7T linux_raid_member part
我尝试 mdadm 组装然后安装它，但失败了。
$ sudo mdadm --assemble --scan --force
$ sudo mount /dev/md0 /home/bilgen/
mount: /home/person: can't read superblock on /dev/md0.
$ cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : inactive sdc1[2] sda1[1]
7813771264 blocks super 1.2
unused devices: <none>
$ sudo mdadm --examine --scan
ARRAY /dev/md/0 metadata=1.2 UUID=92fd33d9:351dcee8:c809916a:b46055e5 name=zencefil:0
验证 RAID 磁盘 sda1 和 sdc1。 sda1 的状态为 clean，但 sdc1 的状态为 active。我认为这对于调试问题很重要。我确认它是 RAID-5，但其中一个磁盘应该已经损坏，因为我拿到计算机时只观察到两个磁盘。现在我意识到了。
$ sudo mdadm -E /dev/sda1
/dev/sda1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 92fd33d9:351dcee8:c809916a:b46055e5
Name : zencefil:0
Creation Time : Thu Mar 12 00:17:27 2015
Raid Level : **raid5**
Raid Devices : **3**
Avail Dev Size : 7813771264 (3725.90 GiB 4000.65 GB)
Array Size : 7813770240 (7451.79 GiB 8001.30 GB)
Used Dev Size : 7813770240 (3725.90 GiB 4000.65 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262064 sectors, after=1024 sectors
**State : clean**
Device UUID : 6212bf12:f2bacb20:6a10a588:ac50cb2d
Update Time : Mon Jan 24 20:04:23 2022
Checksum : cfb60638 - correct
Events : 6360009
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 1
Array State : .AA ('A' == active, '.' == missing, 'R' == replacing)
$ sudo mdadm -E /dev/sdc1
/dev/sdc1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 92fd33d9:351dcee8:c809916a:b46055e5
Name : zencefil:0
Creation Time : Thu Mar 12 00:17:27 2015
Raid Level : **raid5**
Raid Devices : **3**
Avail Dev Size : 7813771264 (3725.90 GiB 4000.65 GB)
Array Size : 7813770240 (7451.79 GiB 8001.30 GB)
Used Dev Size : 7813770240 (3725.90 GiB 4000.65 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262064 sectors, after=1024 sectors
**State : active**
Device UUID : daef079b:176d487a:cb152bdb:3d2548f9
Update Time : Mon Jan 24 20:04:23 2022
Checksum : cf7e70ca - correct
Events : 6360009
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 2
Array State : .AA ('A' == active, '.' == missing, 'R' == replacing)
消息可以帮助了解情况
dmesg | grep md0
[ 8.147671] md/raid:md0: not clean -- starting background reconstruction
[ 8.147750] md/raid:md0: device sdc1 operational as raid disk 2
[ 8.147755] md/raid:md0: device sda1 operational as raid disk 1
[ 8.149553] md/raid:md0: cannot start dirty degraded array.
[ 8.149943] md/raid:md0: failed to run raid set.
[ 2878.821074] EXT4-fs (md0): unable to read superblock
事情变得越来越有趣
mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Thu Mar 12 00:17:27 2015
Raid Level : raid5
Used Dev Size : 18446744073709551615
Raid Devices : 3
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Jan 24 20:04:23 2022
State : active, FAILED, Not Started
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Consistency Policy : unknown
Name : zencefil:0
UUID : 92fd33d9:351dcee8:c809916a:b46055e5
Events : 6360009
Number Major Minor RaidDevice State
- 0 0 0 removed
- 0 0 1 removed
- 0 0 2 removed
- 8 1 1 sync /dev/sda1
- 8 33 2 sync /dev/sdc1