This past weekend my media NAS server was intolerably slow. When I investigated, I found out that one of the RAID-1 partitions is experiencing read errors and is timing out. I decided to risk a reboot and to my surprise the RAID-1 partition did not recover with one fail drive, but mdstat recorded with an inactive status, something like this:
md2 : inactive sdc1(S)
After some Google search, I found that I had to do the following to resurrect the md2 device.
madam --stop /dev/md2 mdadm --assemble --force /dev/md2
This reactivated the md2 partition. I replaced the failed drive and re-added the new drive to the md2 device. The RAID-1 partition is now rebuilding.
The inactive state is a new experience for me, so this was a bit of a surprise.
During this exercise I also found out that the SATA connectors on my SATA add-on card were loose causing intermittent connections. I will have to find a way to address this in the future.