number of imapd processes never decrease

Konrad Mauz kmauz at
Fri Sep 18 01:29:50 EDT 2015

Am 17.09.2015 16:18, schrieb Vladislav Kurz:
> On Thursday 17 of September 2015 you wrote:
>> I would consider how many users you have connected as well as each type of
>> device. If you are running some type of AS setup, each device will
>> maintain an open connection and cause a process to happen. How many users?
> What do you mean by AS setup? Autonomous system? nothing like that.
> Clients use thunderbird, outlook, mobile phones, webmail.

I think Paul mean AS = Active Sync.

> I don't know the exact number of imap users, because some users still use pop3
> (which has short-lived connections). Currently there are about 200 imapd
> processes. (Plus another 60 "imapd -s").
> I think every client is going to be turned off, rebooted, or out of battery
> from time to time. So I feel like there are some processes "forgotten",
> keeping the connection with nobody on the other end.

I think this too. Yesterday afternoon I changed the imapd.conf 
configoption "tcp_keepalive" from 0 to 1.
The number of imapd processes dropped from 2800 ( yesterday 7:00am ) to 
arround 1000 ( today 7:00am ).

When I understand tcp keepalive correctly, the systems now checks from 
time to time ( every 2 hours by default on linux systems ) with an ACK 
if the tcp connection endpoint is still reachable.

I am neither an cyrus nor an tcp/ip expert, so a comment from an expert 
would be nice.




Hochschule Konstanz - Rechenzentrum
Konrad Mauz kmauz at
Tel: +497531206-472, Fax: -153

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 5423 bytes
Desc: S/MIME Cryptographic Signature
Url : 

More information about the Info-cyrus mailing list