Re: DM limits setup

[Joe Thornber <thornber@redhat.com>]

On Wed, Dec 31, 2014 at 02:10:52PM -0800, Doug Dumitru wrote:
> Hello all,
> 
> I have a test dm target module that I use to validate storage subsystems
> for data accuracy.  It basically builds weak hashes for every sector of a
> device when written, and validates these hashes when the sector is read
> back.  Ugly memory usage, but it is just a test tool.
> 
> I can deploy this with an iterator target and it will take on the limits of
> the device underneath, or I can skip the iterator target and get limits at
> 2048 sectors.  What I would like to do is set the limit manually.  I know
> this is "really bad program design", but again, this is a test tool and not
> anything for production use.
> 
> Can anyone point me at an example of where the limits are setup explicitly.

Hi Doug,

This sounds like a useful target for testing, any chance you could
post it here when you finish it please?

dm-thin does lots of tweaking of limits, so that's probably the best one to look at:

https://github.com/jthornber/linux-2.6/blob/thin-dev/drivers/md/dm-thin.c#L3707

- Joe