memcached timeouts
Nathan Schmidt
nschmidt at gmail.com
Mon May 5 19:47:44 UTC 2008
Evert,
To reinforce Miguel's point, something we ran into was having two
subnets (separate /27 ip blocks) on the same switch. If you don't
hardcode combined routing for both subnets you'll end up routing some
app-to-memcached traffic upstream to your router and back, which can
cause occasional failures and timeouts depending on the quality of the
upstream connectivity. This was particularly a factor for us because
we have Gig-E on our backplane but our upstream traffic is over a
100mbps PHY.
-n
On Mon, May 5, 2008 at 12:13 PM, Miguel DeAvila
<miguel.j.deavila at gmail.com> wrote:
>
> On Monday 05 May 2008 12:05:26 Evert | Rooftop wrote:
> > I'm getting timeouts trying to connect to memcached. The odd thing is
> > that the timeouts only occur from 1 single webserver, to 1 single
> > memcached box:
> >
> > Memcache::get() [<a href='function.Memcache-get'>function.Memcache-
> > get</a>]: Server www5 (tcp 11211) failed with: Connection timed out
> > (110)
> >
> > Other boxes connecting to that memcached instance work fine, and that
> > webserver connecting to other memcached instances also have no issues.
> >
> > This might well be a problem somewhere completely else, but I was
> > hoping someone on this list can advice on how to track down the exact
> > problem. What is a good starting point?
>
> - ping from the affected web server to the affected memcache server
> - nc from the affected web server to the affected memcache server
> - compare output of /sbin/route on affected web server with normally-functioning web server
>
>
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