Disk Throughput test

[Chuck Swiger]

On Oct 23, 2008, at 8:27 AM, Stephen Sanders wrote:
> 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.

Are you using RAID-5 or RAID-10 config?  RAID-5 is best suited for  
read-only or read-mostly volumes; if you are doing an even mix  
RAID-1/10 will generally perform better.

> 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?

You can also try running diskinfo -t to look for raw performance  
numbers; if they are much different from the bandwidth your app is  
getting, perhaps you need to tune your app...

Regards,
-- 
-Chuck