[Solved] NAS540 Volume Down ~

Andrew

This is RAID 5 on NAS540.

One disk has degraded, but clicked the repair option, no help. 

I can access the web interface, but not able to access my files.
Can use any commands to fix this problem?

Thank you in advance!


#NAS_Sep_2019

Mijzelf

mdadm tells the array has only 2 members left, sdc3 being 'Active device 2', and sdd3 being 'Active device 3'.
For some reason sda3 is marked as spare, possibly because you have removed it and powered the box, but the should be either be 'Active device 0' or 1. 
Of course 0 is the most probable, because then the logical order of the disks is identical to the physical order.

The only way I know to re-add sda3 to the array is to re-create the array, with the flag --assume-clean to keep the raid manager from changing the content.

The command to build A.AA is

mdadm --stop /dev/md2<br>mdadm --create --assume-clean --level=5&nbsp; --raid-devices=4 --metadata=1.2 --chunk=64K&nbsp; --layout=left-symmetric /dev/md2 /dev/sda3 missing /dev/sdc3&nbsp; /dev/sdd3

That are 2 lines, both starting with mdadm. The first might throw an error, don't know if device md2 is present. /proc/mdstat says yes, /proc/partitions says no.

If the array is re-created, (shouldn't take much time, a few seconds) you can reboot the box with

reboot

and after that your volume should be available.