On Tue, Feb 24, 2009 at 4:04 PM, Joseph L. Casale <jcas...@activenetwerx.com> wrote: >>> ... mirror ... performance was fine ... >>> The RAID5 part was still horribly slow. >> >> Short version: Your RAID controller stinks. Buy a better one. > > Well, R5 performance is not ever going to be as good as R1 (at least in that > scenario).
Not true. With a sophisticated RAID controller and a good XOR coprocessor, and enough disks, RAID5 writes can actually be faster than RAID1, because writes can be striped across several physical units. Mirroring will generally only ever be as fast as a single disk for writes, and twice as fast for reads. It's all about whether the RAID controller can perform the XOR calculations on blocks to be written faster than the physical units can accept the data. If the controller is faster, the disks are the bottleneck. If the disks are faster, the controller is the bottleneck. -- Ben ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
