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RAIDディスクを別のシステムでマウント
=================================

概要
----

OpenWRTのRAID-1(ミラーリング)で運用していたディスクを取り外し、1台だけ別のシステム(具体的にはRaspberry Pi)に接続してマウントする。
一般的なLinuxシステムでも同じ方法でできるはず。
手順
----

mdadmをインストール

```
sudo apt install mdadm
```



取り外したHDDを適当なHDDケースに入れて、RaspberryPiにUSB接続する。

そのときのdmesgの抜粋

```
[ 6150.566933] usb 2-2: new SuperSpeed USB device number 2 using xhci_hcd
[ 6150.588314] usb 2-2: New USB device found, idVendor=152d, idProduct=0578, bcdDevice=72.05
[ 6150.588337] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 6150.588349] usb 2-2: Product: GW3.5AM-SU3P
[ 6150.588359] usb 2-2: Manufacturer: Kuroutoshikou
[ 6150.588368] usb 2-2: SerialNumber: 0C51800004CB
[ 6150.630844] scsi host0: uas
[ 6150.632117] scsi 0:0:0:0: Direct-Access     ST3000DM 007-1WY10G       7205 PQ: 0 ANSI: 6
[ 6150.706932] sd 0:0:0:0: [sda] 5860533168 512-byte logical blocks: (3.00 TB/2.73 TiB)
[ 6150.706952] sd 0:0:0:0: [sda] 4096-byte physical blocks
[ 6150.707175] sd 0:0:0:0: [sda] Write Protect is off
[ 6150.707182] sd 0:0:0:0: [sda] Mode Sense: 53 00 00 08
[ 6150.707533] sd 0:0:0:0: [sda] Disabling FUA
[ 6150.707540] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 6150.741115] sd 0:0:0:0: Attached scsi generic sg0 type 0
[ 6150.763114] sd 0:0:0:0: [sda] Preferred minimum I/O size 4096 bytes
[ 6150.763130] sd 0:0:0:0: [sda] Optimal transfer size 33553920 bytes not a multiple of preferred minimum block size (4096 bytes)
[ 6150.811705]  sda: sda1 sda2 sda3
[ 6150.812083] sd 0:0:0:0: [sda] Attached SCSI disk
[ 6150.922693] block device autoloading is deprecated and will be removed.
[ 6150.938755] block device autoloading is deprecated and will be removed.
[ 6150.971161] block device autoloading is deprecated and will be removed.
[ 6150.994442] md/raid1:md125: active with 1 out of 2 mirrors
[ 6151.066078] md125: detected capacity change from 0 to 5850827520
hiroshi@omvpi:~ $ 
hiroshi@omvpi:~ $ 
```


```
hiroshi@omvpi:~ $ sudo fdisk -l /dev/sda
Disk /dev/sda: 2.73 TiB, 3000592982016 bytes, 5860533168 sectors
Disk model: 007-1WY10G      
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 36F7B8D6-ED67-4C9C-A0A9-51CD930408B4

Device       Start        End    Sectors  Size Type
/dev/sda1       64    8388671    8388608    4G Linux RAID
/dev/sda2  8388672    9437247    1048576  512M Linux RAID
/dev/sda3  9437248 5860529072 5851091825  2.7T Linux RAID
hiroshi@omvpi:~ $ 
```

```
hiroshi@omvpi:~ $ ls -l /dev/md*
brw-rw---- 1 root disk 9, 125 Jan 26 21:19 /dev/md125
brw-rw---- 1 root disk 9, 126 Jan 26 21:19 /dev/md126
brw-rw---- 1 root disk 9, 127 Jan 26 21:19 /dev/md127

/dev/md:
total 0
lrwxrwxrwx 1 root root 8 Jan 26 21:19 OpenWrt:3 -> ../md125
hiroshi@omvpi:~ $ 
hiroshi@omvpi:~ $ cat /proc/mdstat 
Personalities : [raid1] 
md125 : active (auto-read-only) raid1 sda3[0]
      2925413760 blocks super 1.2 [2/1] [U_]
      bitmap: 3/22 pages [12KB], 65536KB chunk

md126 : inactive sda2[0](S)
      522240 blocks super 1.2
       
md127 : inactive sda1[0](S)
      4189184 blocks super 1.2
       
unused devices: <none>
hiroshi@omvpi:~ $ 
```


マウントすることで、中身にアクセスできた。
（リードオンリーのようだけど、データを救い出せることが分かったので目的は達せられた）

```
hiroshi@omvpi:~ $ sudo mkdir /mnt/hdd{1,2,3}
hiroshi@omvpi:~ $ sudo mount /dev/md125 /mnt/hdd3
hiroshi@omvpi:~ $ ls -l /mnt/hdd3
total 32
drwxr-xr-x 3 root   root  4096 May 28  2022 homes
drwx------ 2 root   root 16384 May 28  2022 lost+found
drwxrwxrwx 8 nobody root  4096 Oct 15  2022 share
-rw-r--r-- 1 root   root    29 May 28  2022 TESTFILE
drwxr-xr-x 6 nobody root  4096 Nov 23  2022 users
hiroshi@omvpi:~ $ 

```


---

有効になっていないパーティションも読めるようにする。

```
hiroshi@omvpi:~ $ cat /proc/mdstat
Personalities : [raid1] 
md125 : active raid1 sda3[0]
      2925413760 blocks super 1.2 [2/1] [U_]
      bitmap: 3/22 pages [12KB], 65536KB chunk

md126 : inactive sda2[0](S)
      522240 blocks super 1.2
       
md127 : inactive sda1[0](S)
      4189184 blocks super 1.2
       
unused devices: <none>
hiroshi@omvpi:~ $



```

md126,md127には (S) がついている。

```
hiroshi@omvpi:~ $ sudo mdadm --run /dev/md126
mdadm: failed to start array /dev/md/OpenWrt:2: Invalid argument
hiroshi@omvpi:~ $
hiroshi@omvpi:~ $ sudo mdadm --run /dev/md127
mdadm: started array /dev/md/OpenWrt:1
hiroshi@omvpi:~ $
```

このときのdmesg
```
[ 6737.102710] mount: attempt to access beyond end of device
               md127: rw=4096, sector=2, nr_sectors = 2 limit=0
[ 6737.102743] EXT4-fs (md127): unable to read superblock
[ 7090.786977] md/raid0:md126: too few disks (1 of 2) - aborting!
[ 7090.787005] md: pers->run() failed ...
[ 7106.421829] md/raid1:md127: active with 1 out of 2 mirrors
[ 7106.421938] md127: detected capacity change from 0 to 8378368
[ 7302.314628] EXT4-fs (md127): mounted filesystem d6426954-4eed-4d17-af56-85f15dfce2b8 r/w with ordered data mode. Quota mode: none.
```

```
hiroshi@omvpi:~ $ cat /proc/mdstat
Personalities : [raid1] [raid0] 
md125 : active raid1 sda3[0]
      2925413760 blocks super 1.2 [2/1] [U_]
      bitmap: 3/22 pages [12KB], 65536KB chunk

md126 : inactive sda2[0]
      522240 blocks super 1.2
       
md127 : active (auto-read-only) raid1 sda1[0]
      4189184 blocks super 1.2 [2/1] [U_]
      
unused devices: <none>
hiroshi@omvpi:~ $ 
```

md126 は、もともとOrenWRTにあったときから、うまく動いてなかったので無視。
md127 を -run すると、有効になった。

```
hiroshi@omvpi:~ $ sudo mount /dev/md127 /mnt/hdd1
hiroshi@omvpi:~ $ ls -alF /mnt/hdd1
total 32
drwxr-xr-x 5 root root  4096 May 31  2022 ./
drwxr-xr-x 5 root root  4096 Jan 26 21:26 ../
lrwxrwxrwx 1 root root     1 May 31  2022 .fs_state -> 2
drwx------ 2 root root 16384 May 30  2022 lost+found/
drwxr-xr-x 9 root root  4096 May 31  2022 upper/
drwxr-xr-x 3 root root  4096 May 31  2022 work/
hiroshi@omvpi:~ $ 

```


<note>
LinuxのソフトウェアRAID(mdadm)の RAID-1（ミラーリング）を構成していたディスクは、1台だけ取り外してほかのシステムに接続しても、比較簡単に中身を読むことができる。

もともとのマシンがぶっ壊れても、他のマシンにつなげば中身を読めるのは安心感があってよい。
</note>



---


以下は、よく分からずに試行錯誤していたときのログ。
実際にはやる必要のなかった無駄な操作が多く含まれているが、何かの参考になるかもしれないので残しておく。

```
hiroshi@omvpi:~ $ dmesg
        :
[ 8929.274103] usb 1-1.2: new high-speed USB device number 3 using xhci_hcd
[ 8929.471725] usb 1-1.2: New USB device found, idVendor=152d, idProduct=9561, bcdDevice=81.36
[ 8929.471749] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=5
[ 8929.471762] usb 1-1.2: Product: JMS56x Series
[ 8929.471772] usb 1-1.2: Manufacturer: JMicron
[ 8929.471781] usb 1-1.2: SerialNumber: 00000000000000000000
[ 8929.482805] scsi host0: uas
[ 8929.486632] scsi 0:0:0:0: Direct-Access     ST3000DM 007-1WY10G       8136 PQ: 0 ANSI: 6
[ 8929.522498] sd 0:0:0:0: [sda] 5860533168 512-byte logical blocks: (3.00 TB/2.73 TiB)
[ 8929.522865] scsi 0:0:0:1: Direct-Access     ST3000DM 007-1WY10G       8136 PQ: 0 ANSI: 6
[ 8929.523223] sd 0:0:0:0: [sda] Write Protect is off
[ 8929.523232] sd 0:0:0:0: [sda] Mode Sense: 67 00 10 08
[ 8929.524723] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, supports DPO and FUA
[ 8929.525334] sd 0:0:0:0: [sda] Preferred minimum I/O size 4096 bytes
[ 8929.525343] sd 0:0:0:0: [sda] Optimal transfer size 33553920 bytes not a multiple of preferred minimum block size (4096 bytes)
[ 8929.601685] sd 0:0:0:1: [sdb] 5860533168 512-byte logical blocks: (3.00 TB/2.73 TiB)
[ 8929.602395] sd 0:0:0:1: [sdb] Write Protect is off
[ 8929.602413] sd 0:0:0:1: [sdb] Mode Sense: 67 00 10 08
[ 8929.604127] sd 0:0:0:1: [sdb] Write cache: enabled, read cache: enabled, supports DPO and FUA
[ 8929.604679]  sda: sda1 sda2 sda3
[ 8929.604841] sd 0:0:0:1: [sdb] Preferred minimum I/O size 4096 bytes
[ 8929.604856] sd 0:0:0:1: [sdb] Optimal transfer size 33553920 bytes not a multiple of preferred minimum block size (4096 bytes)
[ 8929.605963] sd 0:0:0:0: [sda] Attached SCSI disk
[ 8929.611992] sd 0:0:0:1: [sdb] Attached SCSI disk
[ 8929.621925] sd 0:0:0:0: Attached scsi generic sg0 type 0
[ 8929.622143] sd 0:0:0:1: Attached scsi generic sg1 type 0
[ 8930.035279] block device autoloading is deprecated and will be removed.
[ 8930.039552] block device autoloading is deprecated and will be removed.
[ 8930.050350] block device autoloading is deprecated and will be removed.
        :
		
hiroshi@omvpi:~ $ sudo fdisk -l /dev/sd?
Disk /dev/sda: 2.73 TiB, 3000592982016 bytes, 5860533168 sectors
Disk model: 007-1WY10G      
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 36F7B8D6-ED67-4C9C-A0A9-51CD930408B4

Device       Start        End    Sectors  Size Type
/dev/sda1       64    8388671    8388608    4G Linux RAID
/dev/sda2  8388672    9437247    1048576  512M Linux RAID
/dev/sda3  9437248 5860529072 5851091825  2.7T Linux RAID


Disk /dev/sdb: 2.73 TiB, 3000592982016 bytes, 5860533168 sectors
Disk model: 007-1WY10G      
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
hiroshi@omvpi:~ $ 
hiroshi@omvpi:~ $ ll /dev/md*
-bash: ll: command not found
hiroshi@omvpi:~ $ ls -l /dev/md*
brw-rw---- 1 root disk 9, 125 Jan 25 22:30 /dev/md125
brw-rw---- 1 root disk 9, 126 Jan 25 22:30 /dev/md126
brw-rw---- 1 root disk 9, 127 Jan 25 22:30 /dev/md127
hiroshi@omvpi:~ $

* /dev/sda が openwrt から取り外した RAID-1 を構成していたディスクのうちの1本

hiroshi@omvpi:~ $ cat /proc/mdstat 
Personalities : [linear] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md125 : inactive sda3[0](S)
      2925413816 blocks super 1.2
       
md126 : inactive sda1[0](S)
      4189184 blocks super 1.2
       
md127 : inactive sda2[0](S)
      522240 blocks super 1.2
       
unused devices: <none>
hiroshi@omvpi:~ $ 

hiroshi@omvpi:~ $ sudo mdadm --detail /dev/md*
/dev/md125:
           Version : 1.2
        Raid Level : raid1
     Total Devices : 1
       Persistence : Superblock is persistent

             State : inactive
   Working Devices : 1

              Name : OpenWrt:3
              UUID : bee41517:55b3802c:f9404605:bc06b2d9
            Events : 20919

    Number   Major   Minor   RaidDevice

       -       8        3        -        /dev/sda3
/dev/md126:
           Version : 1.2
        Raid Level : raid1
     Total Devices : 1
       Persistence : Superblock is persistent

             State : inactive
   Working Devices : 1

              Name : OpenWrt:1
              UUID : d1675450:f945d915:a2ae2789:536908f1
            Events : 48

    Number   Major   Minor   RaidDevice

       -       8        1        -        /dev/sda1
/dev/md127:
           Version : 1.2
        Raid Level : raid0
     Total Devices : 1
       Persistence : Superblock is persistent

             State : inactive
   Working Devices : 1

              Name : OpenWrt:2
              UUID : 133d7fd3:01209fbf:5004cb32:421736b5
            Events : 0

    Number   Major   Minor   RaidDevice

       -       8        2        -        /dev/sda2
hiroshi@omvpi:~ $ 



    Number   Major   Minor   RaidDevice
       -       8        3        -        /dev/sda3
       -       8        1        -        /dev/sda1
       -       8        2        -        /dev/sda2


＊ mdadm.conf の内容（初期状態）

hiroshi@omvpi:~ $ cat /etc/mdadm/mdadm.conf 
# mdadm.conf
#
# !NB! Run update-initramfs -u after updating this file.
# !NB! This will ensure that initramfs has an uptodate copy.
#
# Please refer to mdadm.conf(5) for information about this file.
#

# by default (built-in), scan all partitions (/proc/partitions) and all
# containers for MD superblocks. alternatively, specify devices to scan, using
# wildcards if desired.
#DEVICE partitions containers

# automatically tag new arrays as belonging to the local system
HOMEHOST <system>

# instruct the monitoring daemon where to send mail alerts
MAILADDR root

# definitions of existing MD arrays

# This configuration was auto-generated on Sat, 18 Jan 2025 23:15:35 +0900 by mkconf
hiroshi@omvpi:~ $ 

hiroshi@omvpi:~ $ lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda           8:0    0  2.7T  0 disk 
├─sda1        8:1    0    4G  0 part 
│ └─md126     9:126  0    0B  0 md   
├─sda2        8:2    0  512M  0 part 
│ └─md127     9:127  0    0B  0 md   
└─sda3        8:3    0  2.7T  0 part 
  └─md125     9:125  0    0B  0 md   
sdb           8:16   0  2.7T  0 disk 
mmcblk0     179:0    0  7.4G  0 disk 
├─mmcblk0p1 179:1    0  512M  0 part /boot/firmware
└─mmcblk0p2 179:2    0  6.9G  0 part /var/folder2ram/var/cache/samba
                                     /var/folder2ram/var/lib/monit
                                     /var/folder2ram/var/lib/rrdcached
                                     /var/folder2ram/var/spool
                                     /var/folder2ram/var/lib/openmediavault/rrd
                                     /var/folder2ram/var/tmp
                                     /var/folder2ram/var/log
                                     /
hiroshi@omvpi:~ $ 

hiroshi@omvpi:~ $ sudo parted /dev/md125 print
Warning: Error fsyncing/closing /dev/md125: Input/output error
Retry/Ignore? r                                                           
Warning: Error fsyncing/closing /dev/md125: Input/output error
Retry/Ignore? i                                                           
hiroshi@omvpi:~ $ sudo parted /dev/md126 print
Warning: Error fsyncing/closing /dev/md126: Input/output error
Retry/Ignore? i                                                           
hiroshi@omvpi:~ $ sudo parted /dev/md127 print
Warning: Error fsyncing/closing /dev/md127: Input/output error
Retry/Ignore? i                                                           
hiroshi@omvpi:~ $ 

＊ OpenWRTでは、どんな風になっていたのか（現行のディスクをチェックしてみる）



BusyBox v1.35.0 (2023-01-03 00:24:21 UTC) built-in shell (ash)

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 -----------------------------------------------------
 OpenWrt 22.03.3, r20028-43d71ad93e
 -----------------------------------------------------
root@OpenWrt:~# 
root@OpenWrt:~# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/root                 3072      3072         0 100% /rom
tmpfs                   125772     87464     38308  70% /tmp
/dev/ubi0_1             106184     21136     80208  21% /overlay
overlayfs:/overlay      106184     21136     80208  21% /
tmpfs                      512         0       512   0% /dev
/dev/md3             5762648500 3634764892 1835083632  66% /mnt/md3
/dev/md1               4041440     44160   3771440   1% /mnt/md1
root@OpenWrt:~# cat /proc/mdstat 
Personalities : [raid0] [raid1] [raid10] 
md1 : active raid1 sda1[3] sdb1[2]
      4189184 blocks super 1.2 [2/2] [UU]
      
md3 : active raid1 sda3[3] sdb3[2]
      5855671847 blocks super 1.2 [2/2] [UU]
      bitmap: 0/22 pages [0KB], 131072KB chunk

unused devices: <none>
root@OpenWrt:~# 
Disk /dev/sda: 5.46 TiB, 6001175126016 bytes, 11721045168 sectors
Disk model: WDC WD60EZAZ-00S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 875A90EA-FE1C-4FE0-9649-DB24155B5A85

Device       Start         End     Sectors  Size Type
/dev/sda1       64     8388671     8388608    4G Linux RAID
/dev/sda2  8388672     9437247     1048576  512M Linux RAID
/dev/sda3  9437248 11721045134 11711607887  5.5T Linux RAID


Disk /dev/sdb: 5.46 TiB, 6001175126016 bytes, 11721045168 sectors
Disk model: WDC WD60EZAZ-00S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: F11EE5F2-D7CE-4738-AA86-59F981999363

Device       Start         End     Sectors  Size Type
/dev/sdb1       64     8388671     8388608    4G Linux RAID
/dev/sdb2  8388672     9437247     1048576  512M Linux RAID
/dev/sdb3  9437248 11721045134 11711607887  5.5T Linux RAID
root@OpenWrt:~#
root@OpenWrt:~# mdadm --detail /dev/md*
/dev/md1:
           Version : 1.2
     Creation Time : Mon May 30 21:03:48 2022
        Raid Level : raid1
        Array Size : 4189184 (4.00 GiB 4.29 GB)
     Used Dev Size : 4189184 (4.00 GiB 4.29 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

       Update Time : Sun Jan 26 13:50:51 2025
             State : clean 
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : resync

              Name : OpenWrt:1  (local to host OpenWrt)
              UUID : d1675450:f945d915:a2ae2789:536908f1
            Events : 70

    Number   Major   Minor   RaidDevice State
       3       8        1        0      active sync   /dev/sda1
       2       8       17        1      active sync   /dev/sdb1
/dev/md3:
           Version : 1.2
     Creation Time : Fri May 27 21:35:24 2022
        Raid Level : raid1
        Array Size : 5855671847 (5584.40 GiB 5996.21 GB)
     Used Dev Size : 5855671847 (5584.40 GiB 5996.21 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Sun Jan 26 13:51:22 2025
             State : clean 
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : bitmap

              Name : OpenWrt:3  (local to host OpenWrt)
              UUID : bee41517:55b3802c:f9404605:bc06b2d9
            Events : 24640

    Number   Major   Minor   RaidDevice State
       3       8        3        0      active sync   /dev/sda3
       2       8       19        1      active sync   /dev/sdb3
root@OpenWrt:~# 
root@OpenWrt:~# cat /etc/config/mdadm
config mdadm
        option email root
        # list devices /dev/hd*
        # list devices /dev/sd*
        # list devices partitions

#config array
#       option device /dev/md2
#       option name OpenWrt:2
#       list devices /dev/sda2
#       list devices /dev/sdb2

config array
        option device /dev/md3
        option name OpenWrt:3
        list devices /dev/sda3
        list devices /dev/sdb3

config array
        option device /dev/md1
        option name OpenWrt:1
        list devices /dev/sda1
        list devices /dev/sdb1
root@OpenWrt:~#
root@OpenWrt:~# mdadm --examine --scan /dev/sd[ab][13]
ARRAY /dev/md/3  metadata=1.2 UUID=bee41517:55b3802c:f9404605:bc06b2d9 name=OpenWrt:3
ARRAY /dev/md/1  metadata=1.2 UUID=d1675450:f945d915:a2ae2789:536908f1 name=OpenWrt:1
root@OpenWrt:~# 

* こっちでも同じこと
root@OpenWrt:~# mdadm --examine --brief --scan --config=partitions
ARRAY /dev/md/1  metadata=1.2 UUID=d1675450:f945d915:a2ae2789:536908f1 name=OpenWrt:1
ARRAY /dev/md/3  metadata=1.2 UUID=bee41517:55b3802c:f9404605:bc06b2d9 name=OpenWrt:3
root@OpenWrt:~#





＊ラズパイ側に戻る

こう出てくる
hiroshi@omvpi:~ $ sudo mdadm --examine --brief --scan --config=partitions
ARRAY /dev/md/1  metadata=1.2 UUID=d1675450:f945d915:a2ae2789:536908f1 name=OpenWrt:1
ARRAY /dev/md/2  metadata=1.2 UUID=133d7fd3:01209fbf:5004cb32:421736b5 name=OpenWrt:2
ARRAY /dev/md/3  metadata=1.2 UUID=bee41517:55b3802c:f9404605:bc06b2d9 name=OpenWrt:3
hiroshi@omvpi:~ $

こうなってる
hiroshi@omvpi:~ $ cat /etc/mdadm/mdadm.conf 
# mdadm.conf
#
# !NB! Run update-initramfs -u after updating this file.
# !NB! This will ensure that initramfs has an uptodate copy.
#
# Please refer to mdadm.conf(5) for information about this file.
#

# by default (built-in), scan all partitions (/proc/partitions) and all
# containers for MD superblocks. alternatively, specify devices to scan, using
# wildcards if desired.
#DEVICE partitions containers

# automatically tag new arrays as belonging to the local system
HOMEHOST <system>

# instruct the monitoring daemon where to send mail alerts
MAILADDR root

# definitions of existing MD arrays

# This configuration was auto-generated on Sat, 18 Jan 2025 23:15:35 +0900 by mkconf
hiroshi@omvpi:~ $
hiroshi@omvpi:~ $ ls -alF /dev/md*
brw-rw---- 1 root disk 9, 125 Jan 25 23:31 /dev/md125
brw-rw---- 1 root disk 9, 126 Jan 25 23:31 /dev/md126
brw-rw---- 1 root disk 9, 127 Jan 25 23:31 /dev/md127
hiroshi@omvpi:~ $

hiroshi@omvpi:~ $ sudo mv /etc/mdadm/mdadm.conf /etc/mdadm/mdadm.conf.ORIGINAL
hiroshi@omvpi:~ $ sudo vi /etc/mdadm/mdadm.conf
hiroshi@omvpi:~ $ cat /etc/mdadm/mdadm.conf
ARRAY /dev/md1  metadata=1.2 UUID=d1675450:f945d915:a2ae2789:536908f1 name=OpenWrt:1
ARRAY /dev/md2  metadata=1.2 UUID=133d7fd3:01209fbf:5004cb32:421736b5 name=OpenWrt:2
ARRAY /dev/md3  metadata=1.2 UUID=bee41517:55b3802c:f9404605:bc06b2d9 name=OpenWrt:3
hiroshi@omvpi:~ $ 
hiroshi@omvpi:~ $ sudo mdadm -A -s
hiroshi@omvpi:~ $ 

sudo reboot

hiroshi@omvpi:~ $ sudo rm /dev/md12
md125  md126  md127 
hiroshi@omvpi:~ $ sudo rm /dev/md12*
hiroshi@omvpi:~ $ 
hiroshi@omvpi:~ $ sudo mdadm -A -s
hiroshi@omvpi:~ $ ls /dev/m
mapper/    media0     media1     media2     media3     mem        mmcblk0    mmcblk0p1  mmcblk0p2  mqueue/    
hiroshi@omvpi:~ $ 
hiroshi@omvpi:~ $ 



hiroshi@omvpi:~ $ sudo mdadm --create /dev/md3 --level=1 --raid-devices=1 /dev/sda3
mdadm: '1' is an unusual number of drives for an array, so it is probably
     a mistake.  If you really mean it you will need to specify --force before
     setting the number of drives.
hiroshi@omvpi:~ $ sudo mdadm --create /dev/md3 --level=1 --raid-devices=1 /dev/sda3 --force
mdadm: cannot open /dev/sda3: Device or resource busy
hiroshi@omvpi:~ $





=====
Linux omvpi 6.6.62+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.6.62-1+rpt1 (2024-11-25) aarch64

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Sun Jan 26 15:41:19 2025 from 2001:c90:8440:4e89:e5da:40d5:b3f2:8ab7
hiroshi@omvpi:~ $ ls /dev/md12
md125  md126  md127  
hiroshi@omvpi:~ $ sudo update-initramfs -u
update-initramfs: Generating /boot/initrd.img-6.6.62+rpt-rpi-v8
'/boot/initrd.img-6.6.62+rpt-rpi-v8' -> '/boot/firmware/initramfs8'
update-initramfs: Generating /boot/initrd.img-6.6.62+rpt-rpi-2712
'/boot/initrd.img-6.6.62+rpt-rpi-2712' -> '/boot/firmware/initramfs_2712'
hiroshi@omvpi:~ $


hiroshi@omvpi:~ $ ls -l /dev/md*
brw-rw---- 1 root disk 9, 1 Jan 26 16:37 /dev/md1
brw-rw---- 1 root disk 9, 2 Jan 26 16:37 /dev/md2
brw-rw---- 1 root disk 9, 3 Jan 26 16:37 /dev/md3
hiroshi@omvpi:~ $ 

hiroshi@omvpi:~ $ ls -l /dev/md*
brw-rw---- 1 root disk 9, 1 Jan 26 16:37 /dev/md1
brw-rw---- 1 root disk 9, 2 Jan 26 16:37 /dev/md2
brw-rw---- 1 root disk 9, 3 Jan 26 16:37 /dev/md3
hiroshi@omvpi:~ $ cat /proc/mdstat 
Personalities : [linear] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md3 : inactive sda3[0](S)
      2925413816 blocks super 1.2
       
md2 : inactive sda2[0](S)
      522240 blocks super 1.2
       
md1 : inactive sda1[0](S)
      4189184 blocks super 1.2
       
unused devices: <none>
hiroshi@omvpi:~ $

hiroshi@omvpi:~ $ sudo mount /dev/md3 /mnt/raiddisk3
mount: /mnt/raiddisk3: can't read superblock on /dev/md3.
       dmesg(1) may have more information after failed mount system call.
mount: (hint) your fstab has been modified, but systemd still uses
       the old version; use 'systemctl daemon-reload' to reload.
hiroshi@omvpi:~ $ 

[ 3015.764373] mount: attempt to access beyond end of device
               md3: rw=4096, sector=2, nr_sectors = 2 limit=0
[ 3015.764395] EXT4-fs (md3): unable to read superblock



hiroshi@omvpi:~ $ sudo mkfs.ext4 -n /dev/md3
mke2fs 1.47.0 (5-Feb-2023)
mkfs.ext4: Device size reported to be zero.  Invalid partition specified, or
        partition table wasn't reread after running fdisk, due to
        a modified partition being busy and in use.  You may need to reboot
        to re-read your partition table.

hiroshi@omvpi:~ $ sudo fsck /dev/md3 -p
fsck from util-linux 2.38.1
fsck.ext2: Invalid argument while trying to open /dev/md3
/dev/md3: 
The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem.  If the device is valid and it really contains an ext2/ext3/ext4
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>
 or
    e2fsck -b 32768 <device>

hiroshi@omvpi:~ $
```

```
hiroshi@omvpi:~ $ cat /proc/mdstat 
Personalities : [linear] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md3 : inactive sda3[0](S)
      2925413816 blocks super 1.2
       
md2 : inactive sda2[0](S)
      522240 blocks super 1.2
       
md1 : inactive sda1[0](S)
      4189184 blocks super 1.2
       
unused devices: <none>
hiroshi@omvpi:~ $ sudo mdadm --run /dev/md3
mdadm: started array /dev/md3
hiroshi@omvpi:~ $ sudo mount /dev/md3 /mnt/raiddisk3
mount: (hint) your fstab has been modified, but systemd still uses
       the old version; use 'systemctl daemon-reload' to reload.
hiroshi@omvpi:~ $ ls /mnt/raiddisk3
TESTFILE  homes  lost+found  share  users
hiroshi@omvpi:~ $ ls -l /mnt/raiddisk3
total 32
-rw-r--r-- 1 root   root    29 May 28  2022 TESTFILE
drwxr-xr-x 3 root   root  4096 May 28  2022 homes
drwx------ 2 root   root 16384 May 28  2022 lost+found
drwxrwxrwx 8 nobody root  4096 Oct 15  2022 share
drwxr-xr-x 6 nobody root  4096 Nov 23  2022 users
hiroshi@omvpi:~ $ 

hiroshi@omvpi:~ $ cat /proc/mdstat 
Personalities : [raid1] [linear] [raid0] [raid6] [raid5] [raid4] [raid10] 
md3 : active (auto-read-only) raid1 sda3[0]
      2925413760 blocks super 1.2 [2/1] [U_]
      bitmap: 3/22 pages [12KB], 65536KB chunk

md2 : inactive sda2[0](S)
      522240 blocks super 1.2
       
md1 : inactive sda1[0](S)
      4189184 blocks super 1.2
       
unused devices: <none>
hiroshi@omvpi:~ $ 


```