On Tue, Nov 10, 2009 at 09:46:52PM +1300, Simon Baxter wrote:
What about a simple raid 1 mirror set?
Ok.. short comparison, using a single disk as baseline.
using 2 disks raid0: (striping) ++ double read throughput, ++ double write throughput, -- half the reliability (read: only use with good backup!)
raid1: (mirroring) ++ double read throughput. o same write throughput ++ double the reliability
using 3 disks:
raid0: striping +++ tripple read performance +++ tripple write performance --- third of reliability
raid1: mirroring +++ tripple read performance o same write throughput +++ tripple reliability
raid5: (distributed parity) +++ tripple read performance - lower write performance (not due to the second write but due to the necessary reads) + sustains failure of any one drive in the set
using 4 disks:
raid1+0: ++++ four times the read performance ++ double write performance ++ double reliability
please note: these are approximations and depending on your hardware they may be off by quite a bit.
cheers -henrik