Our guidelines to building RAID for servers
RAID is multiple hard drives that are grouped together to gain better performance and/or failure redundancy. A server should always use RAID rather than a single hard drive.
Depending on how the hard drives are “grouped”, RAID has different types, such as RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, RAID 50, RAID 60, etc.
Here are the DOs and DONTs when we build RAID for servers
- We do not use traditional SATA hard drives which are slow and less reliable
- We do not use software based RAID controllers which are slow
- We do not use RAID 5 with 3 hard drives, which is slow. If we have to use RAID 5, we will use RAID 5 with at least 5 hard drives to improve performance.
- We do not use SSD hard drives yet.
- We use SAS, 15K RPM hard drives
- We use RAID 1 for OS, RAID 10 for data.
- We use RAID 10 with 4~16 hard drives for file servers.
- We use RAID 10 with 6~ 16 hard drives for SQL or Exchange
RAID 10 is our all time favorite RAID type. The more hard drives are grouped in RAID 10, the better performance the server will gain.