Re: sysfs makes scaling suck Re: Asynchronous scsi scanning

[James Bottomley <James.Bottomley@SteelEye.com>]

On Thu, 2007-05-17 at 13:32 -0400, Benjamin LaHaise wrote:
> On Wed, May 16, 2007 at 04:57:52AM +0530, Satyam Sharma wrote:
> > 
> > echo 1 > /sys/module/scsi_mod/.../wait_for_async_scans
> > 
> > somewhere in some script. In fact, the latter method seems simpler,
> > saner, better (in every which way)!
> 
> Please don't force sysfs on people.  Just watch how it keels over and dies 
> when you end up with lots of disks/network interfaces on reasonably sized 
> boxes.  16 statically allocated files per network interface starts being 
> a problem once you've got a few thousand interfaces.  Anything that forces 
> me to use sysfs is not gonna fly.

Well, for that case, you just never enable async scanning

But also, the sysfs with over 4,000 (and higher) devices was
specifically checked by OSDL (actually as part of the CGL testing) some
of the Manoj changes (for unpinning entries etc) were needed to get it
to function, but as of now, I believe an enterprise scaling test works
reasonably well for it ... there certainly wasn't any evidence of it
dying horribly in the tests.

James