Memcache connection errors

[Kamran Nisar]

hmm.. i've been suspecting a network issue, but haven't been able to find
sumthing concrete to support this fact....

the stats have been jumping
from
STAT bytes_read 18542344217
STAT bytes_written 64761742795
to
STAT bytes_read 18549625582
STAT bytes_written 64790479458

during consecutive runs, and it is off peak time for my site.. will be
running it again during peak hours to check that out....

i plan on running a network sniffer , like ntop or any other on a machine in
the network to analyze the traffic flowing between the machines ....to see
the amount of traffic in the network, so i can estimate whether there is a
bottle neck sumwhere in the network....
or is there a better way of doing that :)


On 5/24/06, Steven Grimm <sgrimm at facebook.com> wrote:
>
> I can tell you that when we've seen failures to connect to memcached,
> the problem has always turned out to be a network issue -- most often a
> flaky switch or loose cable. But in this case it sounds like a simple
> capacity problem.
>
> How much data do you run through memcached? You say you moved from a
> gigabit network to a 100Mbps network; that's an order of magnitude less
> available bandwidth for memcached traffic and you may simply be
> saturating the network. You could be saturating your switch, rather than
> maxing out any one machine's capacity; that is even more likely if
> you're sharing a switch with other customers at your hosting provider,
> who might have bursts in traffic that overwhelm the switch without you
> knowing about it.
>
> Look at your memcached stats and see how fast the "bytes_in" and
> "bytes_out" numbers change. If you're pushing a few tens of megabits a
> second, then periodic spikes in traffic could easily overwhelm your
> network.
>
> In any event, if you're seeing 7ms ping times on your local switched
> network, something is definitely wrong there. You should never see that
> on a network that's not pushing up against its capacity limits.
>
> -Steve
>
>
> Kamran Nisar wrote:
> >
> > got zero tx/rx errors...
> >
> >
> > even the ping returned 0% packet loss, though there was sum random
> > sharp jumps in repsonse time
>
>


-- 
Regards
M Kamran Nisar,
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