Re: x86_64 aacraid help

[Samuel Flory <sflory@rackable.com>]

George Glover wrote:
> Hello,
> 
> I have a dual opteron machine, running a cross compiled test7 on a 32 bit
> distro.  2 gigs of ram, irqbalanced, everything seems to run very well -
> except for the aacraid driver.
> 
> It's an Adaptec 2200S, with 5 U320 drives connected (seperate channels
> 3/2).  Each drive seems to read ~70MB/s on it's own, both through the
> aacraid driver and through the onboard fusion mpt controller.  Using
> hardware raid 10 with aacraid reads ~100MB/s, it seems to go no faster -
> regardless of raid levels.  However with software raid, I can nearly
> double that (half on aacraid, half onboard)  I am not able to test it with
> all drives using the onboard controller with software raid due to lack of
> cables and not wanting to destroy the boot drive.
> 
> I am wondering if there is a magical go faster button that I'm missing?
> 

   Try doing reads in the same sized chunks as your raid stripe.  Try 
something like this:

-add to /etc/sysctl.conf:
vm.max-readahead = 256
vm.min-readahead = 128

-"sysctl -e -p /etc/sysctl"

-- 
Once you have their hardware. Never give it back.
(The First Rule of Hardware Acquisition)
Sam Flory  <sflory@rackable.com>