Disk Throughput test
jpaetzel at FreeBSD.org
Thu Oct 23 18:16:07 UTC 2008
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Stephen Sanders wrote:
> FreeBSD 6.3
> Dual Quad Core Xeon 5450 at 3Ghz
> 16GB RAM
> 3Ware 9650SE-ML / 256MB cache
> 14 Seagate 750GB/7200RPM/ST375033ONS SATA drives
> We have an application that is streaming data to disk at the maximum
> rate the controller can sustain. The controller should be able to
> develop something on the order of 600MB/s but we're only getting 450MB/s.
> The application writes about 50GB into a file, closes the file, and then
> starts another file.
> I've set all of the recommended settings from 3ware. I have tried
> various settings for vfs.hirunningspace - various settings include
> everything from 5MB to the cache size of the card (256MB).
> Does anyone know if there is some file system performance limit?
3ware has recently released new firmware for the 9650 and 9690 cards
that makes a huge difference in performance. I've noticed anywhere from
10-25% increases in real world disk I/O performance.
There is no "file system performance limit" that magically caps
sequential read/write speed to some arbitrary value. A lot of factors
come together to give you a max speed.
Obviously you are hitting a bottleneck somewhere that is lower than you
think it should be.
Does 3ware advertise the card is capable of 600 Megs/sec? It seems an
8x pci-e card would be capable of higher performance than that.
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