RAID concepts and setup
What is RAID?
RAID combines multiple disks for:
- Redundancy (survive disk failures)
- Performance (parallel reads/writes)
- Capacity (single large volume)
Common RAID levels (very short)
- RAID 0: striping, no redundancy
- RAID 1: mirroring
- RAID 5: parity, survives 1 disk failure
- RAID 6: double parity, survives 2 disk failures
- RAID 10: mirrors of stripes (good performance + redundancy)
Software RAID (mdadm)
Inspect:
cat /proc/mdstat
sudo mdadm --detail --scan
Create (example: RAID1 with two disks)
sudo mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb /dev/sdc
sudo mdadm --detail /dev/md0
Then create a filesystem and mount as usual.
Notes
- RAID is not a backup
- Monitor SMART data and array health