Cyrus murder scalability

[Vladimir Nikolic]

2.3.7 on frontend and one backend (RedHat 5) and 2.3.9 on the other 
backend (freebsd 6.1).

Most of errors are between frontend (imap2) and freebsd backend 
(imap-old) and protocol is pop3:
Oct 25 20:37:30 imap2 pop3[12945]: connect(imap-old.amis.net) failed: 
Connection timed out
Oct 25 20:37:30 imap2 pop3[12945]: couldn't authenticate to backend server
When this occurs, users are asked to enter their passwords again. There 
is no record in imap-old about this connection.

Problems between frontend and other backend (imap1) with pop3 happens 
when user mailbox is locked:
Oct 25 20:51:10 imap1 pop3[27158]: Unable to lock maildrop user.alext: 
Mailbox is locked by POP server
or when there is something wrong with user's mail client program:
Oct 25 20:51:28 imap2 pop3[23897]: Fatal error: Lost connection to input 
stream

There is also errors regarding imap protocol:
Oct 25 20:52:05 imap2 imap[20960]: Fatal error: Lost connection to 
selected backend
Oct 25 20:52:33 imap2 imaps[7912]: Fatal error: Lost connection to 
selected backend
but it seems that these errors are invisible to the users.

There is no errors regarding lmtp.

Network traffic is 20-30 Mb/s during peak period,  imap1 and imap2 are 
on the same switch (100Mb/s ports), imap-old is on the switch which is 
connected by 1Gb/s whith first switch.

Regards,
Vladimir

Ken Murchison wrote:
> Vladimir Nikolic wrote:
>   
>> Hi,
>>
>> I have questions regarding murder scalability. Untill last week we had 
>> one imap server with about 50000 users and 2TB mailboxes. Server was 
>> overloaded and little slow but there was no troubles like connections 
>> drop and repeatedly asking users for password.
>> Now we have that old server and three new servers in murder 
>> configuration (1 frontend, 1 murder master in 2 backends) and we have 
>> full troubles with users (almost all of them with pop3 accounts) 
>> complaining that mail clients repeatedly asking for password. Logs on 
>> fronted are full of lines:
>>
>> pop3[12914]: couldn't authenticate to backend server
>> pop3[9822]: couldn't authenticate to backend server: authentication failure
>>     
>
> What version of Cyrus?
>
> Do you only have this problem with POP3?  IMAP and LMTP connections are 
> proxied to the backends without any problems?
>
>