I had a problem with my dns-321 not being able to rebuild array after replacing the failed drive. In my case, the web UI was getting stuck even before beginning the array (with no drive activity going on, as described in
this post). I was able to rebuild the array manually using mdadm as described by OP, but I had to get fdisk2 from
this thread first to be able to create partitions. After that I tried running hd_verify as posted by m2k3423, but got errors for missing /mnt/HD_b4, so I did the below two additional manual steps:
- Create filesystems on /dev/hdb1 and /dev/hdb4
- Mount /dev/hdb4 as /mnt/HD_b4
After this, hd_verify went through fine and the web UI seems to be happy. Now I am still concerned that there might be something left to be done (e.g., what is the role of /dev/hdb1 ?) and so would like to check with experts here. I would appreciate any further guidance.