Yes, Linux’ software raid tools could easily be swapped for zfs these days. I still have one array left, and as disks grow old, IOerrors starts to occure. Here are some commands I’ve found useful.
cat /proc/mdstat
mdadm --examine /dev/sdb1
mdadm --examine --scan
mdadm --assemble --scan
smartctl -a /dev/sdx
dumpe2fs
ddrescue
df -h | egrep -v '(overlay|shm|tmpfs)'
And about rsync:
A trailing slash on the source changes this behavior to avoid creating an additional directory level at the destination.
ddrescue comes from the package gddrescue