如何打开我的mdadm RAID-5阵列？

Question

1. 如何打开我的mdadm RAID-5阵列？
2. 如何使这些更改保持不变？

昨晚我重新启动了服务器，发现大约8个月前创建的raid数组没有恢复，我无法访问我的数据。我运行了一堆命令：

几个月前，我在RAID-5数组中添加了一个新的磁盘/dev/sdh，该数组在这之后被挂载到/srv/share。一切似乎都很好，我们有额外的空间，并一直在使用它-实际上，我不确定我们是否重新启动，除了昨晚。RAID-5最初是在ubuntu 18.04下创建的，现在由ubuntu 20.04使用。

$ cat /proc/mdstat

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : inactive sdf[3](S) sdb[1](S) sda[0](S)
      23441691144 blocks super 1.2
       
unused devices: 


$ lsblk | grep -v loop
NAME   MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda      8:0    0   7.3T  0 disk  
└─md0    9:0    0  21.9T  0 raid5 
sdb      8:16   0   7.3T  0 disk  
└─md0    9:0    0  21.9T  0 raid5 
sdc      8:32   0   4.6T  0 disk  
└─sdc1   8:33   0   4.6T  0 part  /srv/datasets
sdd      8:48   0 298.1G  0 disk  
├─sdd1   8:49   0   190M  0 part  /boot/efi
└─sdd2   8:50   0 297.9G  0 part  /
sde      8:64   0   3.7T  0 disk  
└─sde1   8:65   0   3.7T  0 part  /srv
sdf      8:80   0   7.3T  0 disk  
└─md0    9:0    0  21.9T  0 raid5 
sdg      8:96   0   1.8T  0 disk  
├─sdg1   8:97   0   1.8T  0 part  /home
└─sdg2   8:98   0    47G  0 part  [SWAP]
sdh      8:112  0   7.3T  0 disk  
└─sdh1   8:113  0   7.3T  0 part  


$ sudo fdisk -l | grep sdh
Disk /dev/sdh: 7.28 TiB, 8001563222016 bytes, 15628053168 sectors
/dev/sdh1   2048 15628050431 15628048384  7.3T Linux filesystem



$ sudo mdadm -Db /dev/md0
INACTIVE-ARRAY /dev/md0 metadata=1.2 name=perception:0 UUID=c8004245:4e163594:65e30346:68ed2791
$ sudo mdadm -Db /dev/md/0
mdadm: cannot open /dev/md/0: No such file or directory



From /etc/mdadm/mdadm.conf:
ARRAY /dev/md/0  metadata=1.2 UUID=c8004245:4e163594:65e30346:68ed2791 name=perception:0



$ sudo mdadm --detail /dev/md0 
/dev/md0:
           Version : 1.2
        Raid Level : raid0
     Total Devices : 3
       Persistence : Superblock is persistent

             State : inactive
   Working Devices : 3

              Name : perception:0
              UUID : c8004245:4e163594:65e30346:68ed2791
            Events : 91689

    Number   Major   Minor   RaidDevice

       -       8        0        -        /dev/sda
       -       8       80        -        /dev/sdf
       -       8       16        -        /dev/sdb


sudo mdadm --detail /dev/md/0 
mdadm: cannot open /dev/md/0: No such file or directory



mdadm --assemble --scan
  [does nothing]

$ blkid /dev/md0 [nothing]
$ blkid /dev/md/0 [nothing]

$ blkid | grep raid
/dev/sdb: UUID="c8004245-4e16-3594-65e3-034668ed2791" UUID_SUB="3fefdb86-4c6b-fb76-a35e-3a846075eb54" LABEL="perception:0" TYPE="linux_raid_member"
/dev/sdf: UUID="c8004245-4e16-3594-65e3-034668ed2791" UUID_SUB="d4a58f2c-bc8b-8fd0-6b22-63b047e09c13" LABEL="perception:0" TYPE="linux_raid_member"
/dev/sda: UUID="c8004245-4e16-3594-65e3-034668ed2791" UUID_SUB="afaea924-a15a-c5cf-f9a8-d73075201ff7" LABEL="perception:0" TYPE="linux_raid_member"

/etc/fstab中的相关行是：

UUID=f495abb3-36e6-4782-8f5e-83c6d3fc78eb /srv/share     ext4    defaults        0       2


$ sudo mount -a
mount: /srv/share: can't find UUID=f495abb3-36e6-4782-8f5e-83c6d3fc78eb.

我尝试将fstab中的UUID更改为c8004245:4e163594:65e30346:68ed2791，然后重新装入：

$ sudo mount -a
mount: /srv/share: can't find UUID=c8004245:4e163594:65e30346:68ed2791.

然后我更改为c8004245-4e16-3594-65e3-034668ed2791并重新装入：

$ sudo mount -a
mount: /srv/share: /dev/sdb already mounted or mount point busy.

然后，我使用新的fstab条目重新启动：c8004245-4e16-3594-65e3-034668ed2791

但是，上述任何命令都没有区别^

我尝试将mdadm.conf更改为：

ARRAY /dev/md/0  metadata=1.2 UUID=c8004245:4e163594:65e30346:68ed2791 name=perception:0

至：

ARRAY /dev/md0  metadata=1.2 UUID=c8004245:4e163594:65e30346:68ed2791 name=perception:0

=>没有什么区别吗？

试着停止并从-v开始

$ sudo mdadm --stop /dev/md0
mdadm: stopped /dev/md0

$ sudo mdadm --assemble --scan -v                                   
[ excluding all the random loop drive stuff ]
mdadm: /dev/sdb is identified as a member of /dev/md/0, slot 1.
mdadm: /dev/sdf is identified as a member of /dev/md/0, slot 2.
mdadm: /dev/sda is identified as a member of /dev/md/0, slot 0.
mdadm: added /dev/sdb to /dev/md/0 as 1
mdadm: added /dev/sdf to /dev/md/0 as 2
mdadm: no uptodate device for slot 3 of /dev/md/0
mdadm: added /dev/sda to /dev/md/0 as 0
mdadm: /dev/md/0 has been started with 3 drives (out of 4).


$ dmesg
[  988.616710] md/raid:md0: device sda operational as raid disk 0
[  988.616718] md/raid:md0: device sdf operational as raid disk 2
[  988.616721] md/raid:md0: device sdb operational as raid disk 1
[  988.618892] md/raid:md0: raid level 5 active with 3 out of 4 devices, algorithm 2
[  988.639345] md0: detected capacity change from 0 to 46883371008

cat /proc/mdstat现在说raid是活动的

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid5 sda[0] sdf[3] sdb[1]
      23441685504 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [UUU_]
      bitmap: 0/59 pages [0KB], 65536KB chunk
unused devices: 

mount说/srv/share成功地挂载了

sudo mount -a -v
/                        : ignored
/boot/efi                : already mounted
none                     : ignored
/home                    : already mounted
/srv                     : already mounted
/srv/share               : successfully mounted
/srv/datasets            : already mounted

但/srv/share还是没有出现在df -h里

我仍然看不到/srv/share中的数据

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
udev             32G     0   32G   0% /dev
tmpfs           6.3G  2.5M  6.3G   1% /run
/dev/sdd2       293G   33G  245G  12% /
tmpfs            32G   96K   32G   1% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs            32G     0   32G   0% /sys/fs/cgroup
/dev/sde1       3.6T  455G  3.0T  14% /srv
/dev/sdd1       188M  5.2M  182M   3% /boot/efi
/dev/sdc1       4.6T  3.6T  768G  83% /srv/datasets
/dev/sdg1       1.8T  1.5T  164G  91% /home

Answer 1

这里的答案是https://unix.stackexchange.com/questions/210416/new-raid-array-will-not-auto-assemble-leads-to-boot-problems

有帮助

dpkg-reconfigure mdadm    # Choose "all" disks to start at boot
 update-initramfs -u       # Updates the existing initramfs