Re: sunit not working

[David Chinner <dgc@xxxxxxx>]

On Tue, Jun 12, 2007 at 01:12:15PM +0000, salmr0@xxxxxx wrote:
> 
> Thanks that helps.  Now that I know I have the right sunit and swidth I have
> a performace related question.
> 
> If I do a dd on the raw device or to the lun directy I get speeds of around
> 190-200 MBytes/sec.
> 
> As soon as I add xfs on top of the lun my speeds go to around 150
> MBytes/sec. This is for a single stream write using various block sizes on a
> 2 Gbit/sec fiber channel card.

That's for buffered I/O, right? That sounds about right - if you do two
writes, it should increase a little further. Also, direct I/O should be able
to get you to >90% of the raw device capability....

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group