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Run mdadm - this command is used to manage and monitor software RAID devices in linux.

mdadm --detail /dev/md0 or md<N>

mount -t ext4 /dev/md0 /share/MD0_DATA

Check disks

mdadm --examine /dev/sdd3

cat /proc/mdstat

Add disk back to raid that is "removed"

mdadm --manage /dev/md0 --add /dev/sdd3

After this you should see your raid start to rebuild again.

If that doesn't work check to see if the RAID is online


1 – Download the file to NAS:


2 – Apply execute permission:

chmod +x md_checker

3 – Run the script: ./md_checker

II – Fixing RAID With Usign AFR Command (Safe Way)

If your RAID structure seems “Not Active” and cannt access your files, you can fix this by this way;

Warning; if you’re not sure, don’t do it yourself, contact qnap support!

so we type this command line to fix our RAID;

mdadm -AfR /dev/md0 /dev/sda3 /dev/sdb3 /dev/sdc3 /dev/sdd3

What if we got “missing” or “Rebuildin” HDD? you must fallow right order & dont add “Missing” HDD’s to this command line

1 – Type This command to get RAID back online again;

mdadm -AfR /dev/md0 /dev/sdg3 /dev/sdh3 /dev/sda3 /dev/sdf3 /dev/sdc3 /dev/sdd3 /dev/sdb3

2 – And Now RAID Becomes Active Again!


3 – To mount RAID back again;


4 – Now RAID Comes back, and rebuilding start!

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harvazad commented Jan 2, 2021

When I run “ /etc/init.d/”. I get “no such directory exists”. Any ideas?

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nvpnathan commented Jan 5, 2021

When I run “ /etc/init.d/”. I get “no such directory exists”. Any ideas?

It most have been removed in an update. My QNAP does not have this shell script anymore either.

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