Poor write performance with LSI 320-2 on 6.1-STABLE

[Jeremy Chadwick]

On Thu, Sep 28, 2006 at 05:15:05PM -0500, Albert Chin wrote:
> I don't understand how #1 gives 16MB/s (RAID 1) while #3 gives only
> 17MB/s. I'd expect #3 to be about x2 the performance of #1.
> 
> The arrays are configured with "write-thru" write policy, "adaptive"
> read policy, and "cachedio" cache policy.
> 
> Anything I can do to improve the speed. Even though the bus is 33Mhz,
> I should definitely be doing better than 16MB/s.
>
> {snip}
> 
> I'm running bonnie++ as:
>   $ cd [some tmp dir on UFS2 file system]
>   $ bonnie++

Pure shot in the dark (I have no experience with LSI controllers,
only Adaptec and Promise): have you tried adjusting some of the
tunefs parameters for the UFS2 filesystem bonnie++ is using?
Options -e and -f may help with this.

Also, at least in the Adaptec world: if the controller does its
own caching (that is, it has actual RAM on-board or DRAM of some
kind), it is sometimes *better* to disable SCSI disk caching on
each individual SCSI drive and let the controller do it.  Again,
can't speak for LSI controllers...

-- 
| Jeremy Chadwick                                 jdc at parodius.com |
| Parodius Networking                        http://www.parodius.com/ |
| UNIX Systems Administrator                   Mountain View, CA, USA |
| Making life hard for others since 1977.               PGP: 4BD6C0CB |