On Tue, Dec 11, 2001 at 07:09:14AM -0800, Johnny Lam wrote:
> Hi,
> 
> 	I was wondering if there are hints anyone can provide on how to
> increase the write performance of RAID-5 devices configured with RAIDframe
> on NetBSD-1.5.3_ALPHA.  I've fiddled with different block sizes and
> cylinder counts when newfs'ing, but write performance always roughly an
> order of magnitude slower than read performance.  My setup is 3 SCSI Ultra
> 160 drives on one AIC-7899 controller, and there are 2GB and 15BG partitions
> on each drive devoted to two separate RAID-5 partitions.  The tests I'm
> running are currently just on the RAID-5 composed from the 2GB partitions.
> Typical results from bonnie++ are:
> 
> Version  1.01       ------Sequential Output------ --Sequential Input- --Random-
>                     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
> Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
> flatland       300M  4855  10  4833   2  3398   5 30301  94 37835  18 163.3   2
>                     ------Sequential Create------ --------Random Create--------
>                     -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
>               files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
>                  16    39   6 +++++ +++   162   3    39   6   952  99    75   4
> 
> (using 32 sectors per stripe unit, 8K block sizes, and 16 cylinders per group).

While writing, did you try to run 'systat vmstat', or 'iostat -x -w1', to see
where the bottleneck is ?

--
Manuel Bouyer <bouyer@antioche.eu.org>
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