set kern.cam.scsi_delay to 2000ms on all platforms

[Alexander Best]

On Thu Oct 21 10, Scott Long wrote:
> Ok, I've gotta be a stick in the mud and ask you how you've come to the conclusion that 2000 is better than 5000.  Can you provide your evidence and/or testing results?

i'm running with kern.cam.scsi_delay set to 2000 and haven't experienced any
timeout issues. my original patch lowered kern.cam.scsi_delay to 5000, but
after receiving some feedback on freebsd-current@ [1] i was under the
impression that the majority of people responding to my post considered 5000 to
be too high. Matthew Jacob e.g. wrote that even 2 seconds is more than enough
even for older hardware. John Baldwin also seemed to agree with lowering the
timeout value to 2 seconds.

this timeout value is not intended to wait for devices to initialize upon boot
time. kern.cam.boot_delay must be set in that case. it only applies to the
timeout of already succussefully initialzed devices.

cheers.
alex

[1] http://www.mail-archive.com/freebsd-hackers@freebsd.org/msg158316.html

> 
> Scott
> 
> On Oct 21, 2010, at 12:21 AM, Alexander Best wrote:
> 
> > a few years ago kern.cam.scsi_delay was set from 150000 to 5000. nowadays a
> > value of 2000 should be sufficient even on old/slow hardware.
> > 
> > to have cleaner code it's better to set default value to 2000 instead of doing
> > so in every config file on every platform.
> > 
> > cheers.
> > alex
> > 
> > On Wed Oct 20 10, Scott Long wrote:
> >> You've described the "what" but not the "why".  Why do you want to remove this option?  Why do you want to change its value?
> >> 
> >> Scott
> >> 
> >> On Oct 19, 2010, at 4:11 PM, Alexander Best wrote:
> >> 
> >>> hi there,
> >>> 
> >>> i've posted this patch on freebsd-hackers@, but jhb@ recommended i should also
> >>> send it to freebsd-scsi at . basically what this patch does is to populate
> >>> kern.cam.scsi_delay=2000 as the default value throughout the entire source
> >>> tree. in addition to that it gets rid of some legacy Makefile entries, where
> >>> kern.cam.scsi_delay was set to 150000.
> >>> 
> >>> cheers.
> >>> alex
> >>> 
> >>> -- 
> >>> a13x
> >>> <SCSI_DELAY.diff2>_______________________________________________
> >>> freebsd-scsi at freebsd.org mailing list
> >>> http://lists.freebsd.org/mailman/listinfo/freebsd-scsi
> >>> To unsubscribe, send any mail to "freebsd-scsi-unsubscribe at freebsd.org"
> > 
> > -- 
> > a13x

-- 
a13x