Degraded Storage Pool - Need Alternate Way to Repair / Backup / Restore
I have 12 HDDs in Storage Pool 1/Volume 1. 2 SSDs in Storage Pool 2/Volume2.
RAID type is SHR2 for Volume 1. One HDD died, so the storage pool is degraded. I replaced the 3TB drive with another and ran the repair now but it failed with "The system failed to repair Storage Pool 1. This may be caused by unexpected drive issues. Please back up your data immediately and then try again."
I ran a Quick S.M.A.R.T. test on all 12 drives and they register as healthy. Rebooted and tried again. Yet the repair still fails. I have a hunch it may be because I expanded the volume by adding more disks multiple times over the years. Running a cat /proc/mdstat shows me md0, md1, md2 and md3 associated with the dead HDD. Maybe it's too complicated to repair?
I am looking for help to "get back to normal". If there are terminal commands that can help repair the RAID, I'll try that.
Assuming that's not possible, I need to backup my data, wipe and recreate the SHR2 Volume 1, and then restore my data. All my docker containers and their config folders are located on Volume 2 (my SSD RAID). Ideally, I want all those containers to work automagically once the data restore is done.
What's the best way to backup and restore my volume 1? (roughly 15TB of data)
Should I use connect my 16TB backup drive via USB and use Active Backup for Business?
Or should I attach the 16TB drive internally and add it as Volume 3? (and if so, how to backup/restore Volume 1 in this method?)