Montag, 3. Februar 2014

Synology - change "RAID1 degraded" to "Basic"

On my DS211j I experimented with the disks (added a second disk, created RAID1 and removed second disk again) and at the end I had a degraded RAID1. I wanted to convert this degraded RAID1 back to Basic but it seems that the DSM web page doesn't allow you to do so. I have looked at the disk config before my experiments started and found that a Basic volume on DSM is already a RAID1, but with only one disk. The only difference to the old situation seems to be that now the RAID1 is registered with two disks instead of one.

So all you have to do is to tell mdadm that the RAID device of interest (/dev/md2 in my case = /volume1) is using only one disk instead of two:

mdadm --grow --raid-devices=1 --force /dev/md2
(Yes, it uses a "grow" command even it "shrinks" the number of disks!!)

Immediately after issuing this command the BEEP of the DS211j stopped and in the Storage Manager the volume was displayed as "Basic". Bingo!