performance tuning on perc6 (LSI) controller

[Ivan Voras]

On 26/03/2008, Benjeman J. Meekhof <bmeekhof at umich.edu> wrote:
> Hi Ivan,
>
>  Thanks for the response.  Your response quotes my initial uneven
>  results, but are you also implying that I most likely cannot achieve
>  results better than the later results which use a larger filesystem
>  blocksize?
>
>  gstripe label -v -s 128k test /dev/mfid0 /dev/mfid2
>  #newfs -U -b 65536 /dev/stripe/test
>  #write:  19.240875 secs (558052492 bytes/sec)
>  #read:  20.000606 secs (536854644 bytes/sec)
>
>  (iozone showed reasonably similar results - depending on recordsize
>  would mostly be writing/reading around 500MB/s, though lows of 300MB/s
>  were recorded in some read situations).

Yes, that was my meaning. If I understood you correctly, Linux manages
~~ 800 MB/s on the array, right?

>  I suppose my real question is whether there is some inherent limit in
>  UFS2 or FreeBSD or geom that would prevent going higher than this.
>  Maybe that's really not possible to answer, but certainly I plan to
>  explore a few more configurations.

I'd guess it's UFS(2), but I don't really know. My own benchmarking
was on a different controller (IBM ServeRAID 8) and I got a similar
ratio between Linux and FreeBSD, so I don't think it's the drivers'
fault. ZFS achieves noticeably better results so it's probably not
GEOM's.