I have 2 disks which were the only disks in a Linux RAID 1 array. The RAID information is still readable via mdadm when mounted externally via USB using my 2-bay disk dock. Is there a way I can read data from this array without installing them as internal drives? They were initially created on my QNAP NAS (TS-451+) and all bays of the NAS are occupied. I need to compare data in this array with another RAID 1 array in my NAS.
1 Answer
I was able to pull this together myself.
First step is to find out which device the external USB drives are.
df -h | grep -v qpkg
On a QNAP it's usually at the end of the list showing something like this:
/dev/sdf1 1.8T 1.8T 58.2G 97% /share/external/DEV3302_1
/dev/sdg2 459.8G 362.0G 97.8G 79% /share/external/DEV3305_2
First column is the device name. Usually it's sdf[1-9]
and sdg[1-9]
. Then you can use mdadm
command to run the RAID group:
mdadm -A -R /dev/md0 /dev/sdf3 /dev/sdg3
I used a non-existing device name md0
. I dared not to use an existing one. Last step is to mount the newly started device using mount
command:
mount -t ext4 /dev/md0 /mnt/extusbraid1