I came across the best article I have read to date about RAID by Carla Schroder: Build Your Own RAID Storage Server with Linux
I enjoy her easy to read and understand writing style. She confirmed many of the the things I discovered about RAID in a very concise one page overview.
I like to look at the the Tuxmachines website (one of my favourites) on a daily basis and I came across a link to another Carla Schroder article about RAID: Linux RAID Smackdown: Crush RAID 5 with RAID 10
Some of the highlights from the article:
- Most Linux installers support RAID 0, 1, and 5, but not 10.
- RAID 10 support is still marked as "experimental" in the kernel.
- RAID 10 is shorthand for RAID1+0, a mirrored striped array. Linux RAID 10 needs a minimum of two disks, and you don't have to use pairs, but can have odd numbers
- RAID10 provides superior data security and can survive multiple disk failures
- RAID10 is fast
- RAID10 is considerably faster during recovery— RAID5 performance during a rebuild after replacing a failed disk bogs down as much as 80%, and it can take hours. RAID10 recovery is simple copying.
- RAID5 is susceptible to perpetuating parity and other errors
- RAID 10s main disadvantage is cost, because 50% of storage is duplication. The redundancy in RAID5 peaks at one-third in a three-disk array, and reduces proportionately as you add disks.
-You can use two disks for practice, though on production systems you need four disks to get any real benefit.
Link to article: Linux RAID Smackdown: Crush RAID 5 with RAID 10