On Thu, 23 Apr 2009 15:09:23 +0200, Christopher Smith <csmith@xxxxxxxxxxxxxxxx> wrote: > Gordan Bobic wrote: > >> To pick the optimum RAID block size, look at the disks. What is the >> multi-sector transfer size they can handle? I have not seen any disks >> to date that have this figure at anything other than 16, and >> 16sectors * 512 bytes/sector = 8KB. >> >> So set the RAID block size to 8KB. > > Is this "chunk size" ? Or would chunk size be #disks*8KB ? In the case of software RAID, yes, it is referred to as chunk size. >> This is also why quite frequently a cheap box made of COTS components >> can complete blow away a similar enterprise grade box with 10-100x >> the price tag. > > In fairness, those enterprise boxes typically have dual redundant > controllers with mirrored cache, and other failure-resistant goodies you > can't really do with COTS hardware. ;) Maybe so, but you can still build two complete COTS boxes with no internal redundancy for a fraction of the cost and deal with mirroring and fail-over on server level. Enter RHCS and DRBD. :) Why compromise? Gordan -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
