3w-9xxx module version in FC4

jeff moe at blagblagblag.org
Fri May 13 02:17:33 UTC 2005


Jesse Keating wrote:
> On Thu, 2005-04-28 at 10:49 -0600, jeff wrote:
> 
>>Do either of these versions address the "Extremely high iowait with 
>>3Ware array and moderate disk activity" bug? It's been open for just 
>>over a year & has 259 comments.
>>
>>https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=121434
>>
>>I can confirm this bug with v2.26.02.001, fwiw.
> 
> 
> Most likely not as much as you'd like.  That unfortunately is an
> artifact of 3ware's design.  We never use these systems for high usage
> scenarios like a database server or sometimes even a home directory
> server.  Nearline backup and slow storage is what we consider them
> useful for.  The '9.2' release does have significant performance
> increases (firmware and driver need to be updated) but I don't think
> they'll solve the IO Wait state any time soon.


I can't benchmark it since it's a live system, but the following helped 
with the iowait problem under FC2:

echo 512 > /sys/block/sda/queue/nr_requests

It was suggested on LKML that nr_requests be double queue_depth. I get 
much more even performance now. It no longer bogs down & goes out to 
lunch when I throw a DVD ISO at it, for example.

I also use:
blockdev --setra 16384 /dev/sda

-Jeff




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