Re: Improving RAID5 performance (what disks/configuration?)

[Mark Hahn]

> > AMD K6-233

64M

> [...]
> > 2 x fast/wide/ultra 9.1gig 7200rpm disks (/export) ---> /dev/md0
> [...]
> >               -------Sequential Output-------- ---Sequential Input-- --Random--
> >               -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
> > Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
> >           100 11281 96.0 23991 93.2  9835 80.9 10934 86.4 25079 80.6 393.7  9.3
> 
> Don't these v. high CPU percentages imply that you're pretty much at the
> limit of what your CPU/memory can do?...

sure.  though the real issue is that with 64M, most of this test is merely
buffer/page-cache bandwidth.  always run bonnie with -s of at least
2x physical ram, preferably >= 3x.