Very Poor Raid Card Performance
wmoran at collaborativefusion.com
Tue Jan 16 19:42:56 UTC 2007
In response to "Steven Lowry" <steve at midden.org>:
> On Tue, January 16, 2007 18:13, Bill Moran wrote:
> > In response to "Steven Lowry" <steve at midden.org>:
> >> I have been very impressed with my FreeBSD 6.2 install, I have nearly
> >> everything working but there are a few things which I need help with.
> >> The main problem is my HD performance, it is approx 6x slower than in
> >> windows XP, hopefully there is a solution. I have an LSI Megaraid 8x
> >> with
> >> four drives in a raid 5 configuration, in windows I was getting up to
> >> 60MB/s
> >> transfer rates but in FBSD I am getting up to 9MB/s. I followed the
> >> instructions in the handbook for tuning disks and I have set dma on.
> >> Being new to unix, I have no idea what to try or get system information
> >> too continue troubleshooting.
> >> If anyone could point me in the right direction or to appropriate
> >> documentation
> >> it would be much appreciated.
> > You should provide the details of how you arrived at those numbers.
> > Please provide details of your testing methodology.
> > While it's impossible to compare apples to apples when pitting Windows
> > against FreeBSD, you at least want to be comparing two fruits -- not
> > apples and buffalo steaks or something like that.
> Thanks for your reply,
> I repeatedly copied a 700MB file from one harddrive to the Raid 5 Drive, a
> different file every time so caching won't be a large factor and consistantly
> got 8-9MB/s. Copying such large files is something I do on a daily basis.
> Hardly scientific, more of a real use scenario. Transfer was done via KDE.
And this translated in to MB/s how? Timed with a stopwatch?
Keep in mind that by simply copying, you are testing the speed of the
OS cache, the speed of the filesystem, and the speed of the driver all
at once. We're going to have to narrow it down to isolate the problem.
I can give you advice in FreeBSD, but I don't know how to do it in
Additionally, if the first hard drive performs badly under FreeBSD for
some reason, that would color your results.
> Here is the dmesg output for the controller;
> amr0: <LSILogic MegaRAID 1.53> mem
> 0xfa2f0000-0xfa2fffff,0xfe800000-0xfe8fffff irq 30 at device 14.0 on pci5
> amr0: delete logical drives supported by controller
> amr0: <LSILogic LSI MegaRAID SATA300-8X PCI-X> Firmware 814D, BIOS H431,
> 128MB RAM
> amrd0: <LSILogic MegaRAID logical drive> on amr0
> amrd0: 712392MB (1458978816 sectors) RAID 5 (optimal)
> Not sure what is meant by the delete line.
It means the driver/hardware supports the optional "delete logical
> Motherboard is an Iwill DK8N, Nforce3 Chipset, AMD 8131 PCI-X bridge.
> The nvidia raid is populated by two WD raptors in a raid 1, this holds FBSD,
> the LSI is for data storage.
> Any other information I could supply?
Collaborative Fusion Inc.
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