How do you remember(if you really do :-)) all the different levels and what each level does? Can anyone suggest an easy way to remember?
I remember them in order by the number of punches in the face a failure of any particular level equates to:
RAID 6 - six punches in the face when it fails, because you had two dang parity drives and thought you were really uber safe....until your Adaptec controller said "no arrays detected".
RAID 5 - five punches in the face when it fails, especially when your Adaptec controller says "no arrays detected"....or a second drive fails during a rebuild.
RAID 1 - one punch in the face, especially if you were using a hardware controller and thought you could just take a drive out and grab the data easily...because, hey, it's just a mirror, right?
RAID 0 - zero punches in the face, because you were expecting it and had full backups.
P.S. I do not work for Adaptec.
RAID 0 - Best performance, poor availability, only suitable for temporary files
RAID 10 - Good performance for twice the price, quick expansions, rebuilds are straight disk-disk copies
RAID 5+ - Cheap, poor performance for small random writes (4x), 10+ hour expansions, risky rebuilds, not suitable for hypervisors
- RAID 0 is not RAID, it's just AID. That's easy enough.
- RAID 1 is mirroring. There's one mirrored copy of your data.
- RAID 2 and 3 are byte-level things that are extremely rare and you don't have to worry about or remember
- RAID 4 is rare; nearly the same category as RAID 2 and 3
- RAID 5 can work with five disks. Or only 3... 1 and 10 always need an even number of drives
- RAID 6 is RAID 5 with one more disk for parity
- RAID 10 is really raid 1+0, or sometimes 0+1 (those are opposites but many vendors get it backwards). All the two-digit RAID levels are easy, since they're literally just the other two numbers added together.
People seem to mostly confuse 0 and 1, but it's pretty easy to remember that RAID 0 provides zero help when you lose a disk.
RAID 10 is really RAID 1+0 (simple math! ;-)
RAID 2 to 4 aren't really worth remembering although RAID 4 is what NetApp uses.
Everyone seems to know RAID 5, so you just need to remember that RAID 6 is an extra parity drive. (RAID 6 doesn't really exist, BTW, it's also sometimes called RAID-DP for Dual Parity)
There is no easy way to remember it. One method i can suggest is as below Raid 0(zero means nothing) so no raid: raid with striping and no redundancy Raid 1(is the first level): so mirroring Raid 5: is striping for fast access and parity for redundancy Raid 6: striping plus double parity Raid 10: raid 1 group in striping http://www.slashroot.in/raid-levels-raid0-raid1-raid10-raid5-raid6-complete-tutorial
From a security aspect:
- Raid 0 -> Striping because 0 means No backup if a disk fail
- Raid 1 -> Mirroring because 1 means a backup if a disk fail
0 -> Bad for security, 1 -> Good for security
Usually people only have problems to remember what 0 do and what 1 do.
You also have to remember 5 and may be 6 which is "5 + one(1) more parity information"