[Dovecot] POP3 error

Attila Nagy bra at fsn.hu
Wed Mar 9 00:42:47 EET 2011

  On 03/08/2011 10:37 PM, Robert Schetterer wrote:
> Am 08.03.2011 21:38, schrieb Attila Nagy:
>>   On 03/08/2011 06:51 PM, Charles Marcus wrote:
>>> On 2011-03-08 12:42 PM, Thierry de Montaudry wrote:
>>>> On 08 Mar 2011, at 19:37, Charles Marcus wrote:
>>>>> So... if the httpd process is the one consuming all of the CPU, doesn't
>>>>> it stand to reason that it might be something to do with one of your
>>>>> web
>>>>> apps, and not dovecot?
>>>> But then why was it fine with 1.1.13, which never had once this
>>>> problem in 2 years? or is 2.0.9 slower, or consuming more resources
>>>> to create the problem?
>>> You don't see how it might be possible that 2.0.x does something that
>>> 1.1.x didn't do that your webmail app might not like, without it being a
>>> dovecot bug?
>>> I'm not saying it is or it isn't, but I'd look there first - see if an
>>> update is available for your webmail app... since you were running an
>>> ancient version of dovecot, maybe you're also running an ancient version
>>> of it too?
>> I can see similar problems (subject: "Restarting dovecot-auth stops
>> authentication"), on a different OS, and nothing common in the webmail
>> area.
>> I think this is clearly related to Dovecot. It handles load very badly
>> (well, it seems at least on common OS settings), doesn't just slow down,
>> but starts to refuse clients.
>> It seems to be obvious that the interprocess socket communication is
>> where it fails, so this is what needs to be investigated.
>> Sadly, doing this on a machine, which cries for a deep breath already is
>> not always easy.
> you might upgrade to the latest 2.x code
> as it might possible your using more stuff
> then you had in older versions, after all there was a long performance
> thread on this list , look for it in archives
I'm running the latest 2.x code (well, sort of, I haven't upgraded to 
2.0.10, because of the LDAP bug, so I have both .9 and .11), I've never 
run 1.x on these machines.
I've run qmail and courier. They are pretty different in their 
architecture, where these kind of stuff (unix socket communication 
between persisently running daemons) is not touched, so there can't be a 
problem, where for example five thousand connections are made in the 
same moment to a single socket/process.
There there will be five thousand forks/execs, which won't fail with 
connection refused, they will be served as fast as the machine can 
handle them (modulo available memory/file descriptors/etc of course).

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