Cyrus 2.3.16 : pop3d processes performing reads on files in 'stage.' subdirs.

[Eric Luyten]

On Tue, August 14, 2012 6:50 pm, Bron Gondwana wrote:
> On Tue, Aug 14, 2012, at 01:22 PM, Eric Luyten wrote:
>
>> On Tue, August 14, 2012 1:06 pm, Bron Gondwana wrote:
>>
>>> On Tue, Aug 14, 2012, at 11:07 AM, Eric Luyten wrote:
>>>
>>>
>>>> All,
>>>>
>>>>
>>>>
>>>> Using dtrace on Solaris 10 I was having a look at our Cyrus server
>>>> I/O activity and I cannot explain myself why pop3d processes carry
>>>> out read operations on files in the 'stage.' subdirectories.
>>>
>>> Is it reading them by name, or just the same inode?
>>>
>>
>>
>> There are no long lived links in our 'stage.' subdirs.
>>
>>
>> % !!
>> ls -l /cyr[1-9]/stage./* No match
>> %
>>
>>
>>
>> We do re-use pop3 and imap server processes, though.
>> (-U 10 parameter on pop3d and imapd entries in /etc/cyrus.conf)
>>
>>
>> We also observe writes to the 'stage.' subdirs by imapd processes
>> but this is to be expected, isn't it ? It's the pop3 processes behaviour
>> which is puzzling me.
>
> Yeah, puzzles me too - you can't APPEND messages via pop3, which is the
> only reason that it would need to use the stage directories.


Bron,


I was thinking along the lines "lmtpd processes not having closed file
descriptors on very recently delivered messages" (and there indeed
appears to be a connection between recent delivery and POP3 session)
so I restarted our Cyrus 2.3.16 server with "-U 1" parameters on the
POP3, IMAPD en LMTPD processes.

But ...

This appears to have no effect at all (Solaris 10 here) : all three
types of processes get reused hundreds of times.


Eric Luyten, Computing Centre VUB/ULB.