I'm going to be rebuilding my server, and I want much faster access to my data. I've used RAID 1 and 0 in the past, and decided upon RAID 10 (dedicated RAID card). Then someone told me to use RAID 5+0, then someone else told me to use RAID 6+0.
Assuming the Hardware RAID Card supports each level, what is currently the FASTEST RAID available, given x number of hard drives? Reliability is now another factor, and I am willing to spend money on new drives if a drive (or multiple) fail. I simply want to know what the fastest RAID level is, along with some reliability for recovering from a failure
41 Answer
The fastest (and unsafest) RAID is striping aka RAID 0.
If you are going to use that make sure you have backups.
[Edit: added stuff below]
A very brief RAID summary:
- RAID 0: Split data across several drives. FAST! If one drive fails then you lose all data.
- RAID 1: Write all data to multiple drives. Not faster when writing. Optionally faster when reading since you can read from several disks at one. You lose a lot of disk capacity (if using 2 drives one of them is a copy of the other, so two 1TB drives yield 1TB of space. If you go extra secure with three copies you have 1/3rd total usable space etc).
- RAID 10: Combine at least 4 drives in two pairs. Forming a stripe of mirrors or a mirror of stripes. Used when both speed and safety are needed. You lose half of the disk space.
- RAID 5: Ok when reading. Slower when writing. Advantage: you lose only one disk of capacity. Fine when mostly reading and storing large amounts of data. You lose 1 drive of capacity. You can lose one hard drive without losing any data.
- RAID 6: Same as RAID 5 with two drives of capacity lost. You can lose two hard drives without losing data. Maybe slower than RAID 5 when writing because of non-trivial parity calculations.
If you want maximum speed: Use SSDs and put them in a stripe. But keep backups of important data.
You should always keep backups of all data, a RAID is not a backup. Not even a RAID 6.
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