Re: Read speed

[Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Tue, 05 Feb 2013 12:12:22 -0500
Jeff Blaine <jblaine-GbE5gUWZ6k7k1uMJSBkQmQ@public.gmane.org> wrote:

> Thank you for the thorough reply, Steve. It's nice to
> read of the progress in 2012, but RHEL 6.3 and what is
> supported there is what we have to work with. It is the
> latest supported version, as you surely know, so it
> seems like we'll have to wait quite awhile before
> getting the module's read performance increases.
> 
> We're dealing with 9 US sites, nightly time window (which
> we're exceeding) for transferring large amounts of data
> over 1.5Mbps links).
> 
> Back to the drawing board.
> 
> Thanks again.
> 

I think you're basically out of luck for now...

Long haul links are really a pessimal case for the older code that did
synchronous reads and writes. You spend most of your time waiting
around for the calls to go back and forth.

I believe Sachin is looking at backporting the async read patches for
6.5. The async write code is already in 6.3 (I think). You should
definitely open a support case since documented customer demand helps
us make the case for including these sorts of changes in an update.

-- 
Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>