Re: Problems with the block-layer timeouts

[James Smart]

Jens Axboe wrote:
> > While I'm on the subject, there are a few related items that could be
> > improved.  In my tests, I was generating I/O requests simply by doing
> >
> >       dd if=/dev/sda ...
> >
> > I don't know where the timeouts for these requests are determined, but
> > they were set to 60 seconds.  That seems much too long.
>
> Fully agreed, as Mike mentioned this actually looks like a dumb udev
> rule that didn't have any effect until this generic timeout work. For
> normal IO, something in the 10 second range is a lot more appropriate.

Yes and no. For direct-attach storage with no other initiators, ok. But 
for larger arrays, potentially with multiple initiators - no.  I can 
name several arrays that depend on a 30 second timeout, and a few that, 
underload, require 60 seconds.  I assume that there's usually "best 
practices" guides for the integrators to ensure the defaults are set right.

-- james s
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