How to finish pending mdadm RAID array resync

Let’s see how to clear pending RAID array resync on your Linux server. First check if there are any raid array resync is pending on your server using below command –

/cat/proc/mdstat

Output of the command should be similar as below –

Personalities : [raid1]
md1 : active (auto-read-only) raid1 sda2[0] sdb2[1]
4203104 blocks super 1.2 [2/2] [UU]
resync=PENDING
md0 : active raid1 sda1[0] sdb1[1]
973524352 blocks super 1.2 [2/2] [UU]
unused devices:

As you can see it shows there’s one raid array resync is pending, you can run below command to finish raid array resync –

mdadm –readwrite /dev/md1

In our case the raid array is md1 but that might not be the same in your case so be careful and change the array name before you run that command. Once you ran that command raid array resync will be started. You can check the resync status with the same command that we used to check raid array resync status –

/cat/proc/mdstat

and here’s the output you should have –

Personalities : [raid1]
md1 : active raid1 sda2[0] sdb2[1]
4203104 blocks super 1.2 [2/2] [UU]
[=>……………….] resync = 8.1% (333952/4203104) finish=1.3min speed=47707K/sec
md0 : active raid1 sda1[0] sdb1[1]
973524352 blocks super 1.2 [2/2] [UU]
unused devices:

You can also verify if the resync has finished using the same command.

Feel free to post comments if you face any issues with this tutorial and I would be happy to help. Also, check out these articles –
How to stop RAID check in Linux
How to clear up pending resync on RAID array