How to mount a single hard disk that was part of RAID 1

I will share my experiences below on how I managed to mount a single hard disk that was part of RAID 1 and the issues I’ve encountered during the process.

First, do lsblk to prints all block devices.

1
2
3

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sde      8:64   0   4.5T  0 disk 
└─sde1   8:65   0   4.5T  0 part

In this case, sde1 is what I was looking for.
I proceeded to run the following command:

1	$ mdadm --assemble --run /dev/md2 /dev/sde1

And encountered the following:

1 2	mdadm: Found some drive for an array that is already active: /dev/md/ubuntu:0 mdadm: giving up.

This is caused by mdadm complaining that you’re trying to assemble an array with a UUID matching one already running.
We can fix this by changing the UUID on the /dev/sde1 superblock when we assemble it.

To find the old UUID:

1	$ mdadm --examine /dev/sde1

Results

/dev/sde1:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x1
     Array UUID : e1dc032e:d7d02935:71895af8:53eea165
           Name : ubuntu:0
  Creation Time : Tue Mar 30 18:23:45 2021
     Raid Level : raid1
   Raid Devices : 2

 Avail Dev Size : 9767274496 (4657.40 GiB 5000.84 GB)
     Array Size : 4883637248 (4657.40 GiB 5000.84 GB)
    Data Offset : 264192 sectors
   Super Offset : 8 sectors
   Unused Space : before=264112 sectors, after=0 sectors
          State : clean
    Device UUID : cb083a67:de3131fa:ad29c9a8:7e44fbfb

Internal Bitmap : 8 sectors from superblock
    Update Time : Wed Mar 17 17:36:14 2021
  Bad Block Log : 512 entries available at offset 32 sectors
       Checksum : 6854a473 - correct
         Events : 64302


   Device Role : Active device 0
   Array State : AA ('A' == active, '.' == missing, 'R' == replacing)

Finally, excute ths following command:

1	$ mdadm --assemble /dev/md11 --update=uuid --uuid=<newuuid> /dev/sde1

For me, I just changed the last character to a instead of b:

1	$ mdadm --assemble /dev/md11 --update=uuid --uuid=cb083a67:de3131fa:ad29c9a8:7e44fbfa /dev/sde1

Reference
https://unix.stackexchange.com/questions/267209/mdadm-assembling-another-array-using-device-removed-from-active-one
https://blog.csdn.net/sch0120/article/details/105723017