I recently had a 4 disk array and I migrated to a 2 disk array. I copied all the data from all the prior data disks to to a single drive then created a new config with a new parity drive (18TB no data) and the array disk (18TB with data from the old array disks). Parity was built successfully and no immediate issues were noticed. Now, about a week later, I noticed on my MacBook Pro, Time Machine backups are not completing, smb shares are not mounting. When Time Machine fails, I get a notifications "Backup Disk Not Available" but if I watch the Time Machine preferences as I start a backup, it starts with looking for backup disk and then changes to preparing backup. This to me means it found the disk but for some reason can't write to it.
tower-diagnostics-20220720-0750.zip