KILL 9 exit immediately - this signal may not be blocked and process get killed immediately without saving data. Use this only you need it as
data loss may be possible
TERM 15 send exit request - this signal is sent to a process to request its termination.
Usually you need to use kill command without KILL -9
RAID 1+0 vs 0+1 see
- RAID Levels 0+1 (01) and 1+0 (10)
- Why is RAID 1+0 better than RAID 0+1?