On Mon, Mar 3, 2008 at 2:54 PM, Adam Goryachev <[EMAIL PROTECTED]> wrote: > I was always led to believe that the more drives you had in an array the > faster it would get. ie, comparing the same HDD and controller, if you > have 3 HDD in a RAiD5 it would be slower than 6 HDD in a RAID5.
For most workloads, yes, more spindles will be faster. For small writes (writes smaller than stripe size) to RAID 5, more spindles do not help since performance is limited by the seek time of the slowest disk. For streaming read/writes and random read loads, a 6 disk RAID5 will generally be faster than a 3 disk RAID5. > Is that an invalid assumption? How does RAID6 compare in all this? Would > it be faster than RAID5 for the same number of HDD's ? (Exclude CPU > overheads in all this) As Les mentioned, RAID6 simply adds an additional parity disk so that you can suffer from up to 2 disk failures without losing data. RAID6 itself does not perform any differently than RAID5 and tends to be slightly slower because of the overhead of having to maintain two disks for parity instead of one. -Dave ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ BackupPC-users mailing list [email protected] List: https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki: http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
