Memcache connection errors

Kamran Nisar mkamrannisar at
Wed May 24 15:20:49 UTC 2006

yepsh it was a zero packet lost, the packtes sent is exactly equal to
packets recvd....

have tried it with apache and memcache running on local machines as well..
still got random errors !!

under normal conditions, apache and memcached are running on dedicated
servers, both are 64 bit AMD athlon with the apache machine having 2 GB of
RAM and the memcached one having 4 GB...
the output of uname -a on apache and memcache machine is as

Linux #4 SMP Sun Dec 25 19:45:33 EST 2005
i686 athlon i386 GNU/Linux
with libevent-1.1a

Linux #1 SMP Tue May 9 01:23:27 EDT 2006 i686
athlon i386 GNU/Linux
with  php-5.0.4, and memcache client memcache-2.0.1 (was using 1.5 earlier,
upgraded to 2.0.1 during this process.....)

 (for all the people who asked for the switch config, i have asked the
tech-support to mail me the switch sepcifications.. as i do not have the
model number with me atm as well :$ .. i will be posting the details about
it as well i get it... )

since i am using ab to generate the hits.. the load eventually rises as ab
generates more and more requests  (i am usualy running it a concurrency rate
of 200+)... no susbstantial change on the memcached server though..

On 5/24/06, Jacques Caron <jc at> wrote:
> Hi,
> At 15:29 24/05/2006, Kamran Nisar wrote:
> >got zero tx/rx errors...
> Did you check the switches as well? I guess you have everything
> correctly set to full duplex? What kind of switches are you using?
> >even the ping returned 0% packet loss, though there was sum random
> >sharp jumps in repsonse time
> 0% or packet loss or 0 packets lost? In some situations you may have
> a very low packet loss (under 1%) that is still enough to generate
> some random timeouts, so make sure you check that you received
> exactly as many packets as you sent. Also the increases in response
> times mean you have some kind of network issue, probably a link or
> switching matrix maxing out somewhere.
> You may also want to do a local test (httpd and memcache on the same
> box) if at all possible, to completely isolate network issues vs
> other types of issues. I suppose you don't have any rate-limiting
> filtering rules anywhere? If you can't run the httpd on the same box
> for whatever reason, I guess a short perl (or whatever other
> language) script running GETs on the memcached server (running on the
> same box) in a tight loop while you're running your benchmark will
> let you know whether the issue is local or not.
> What's the load (CPU user/system), and memory usage (RAM, swap,
> pageins/pageouts) during your benchmarks? Is there anything else
> running on the memcached server?
> Jacques.

M Kamran Nisar,
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