[Dovecot] Test environment question

[Timo Sirainen]

The code has some checks that if posix_fallocate() fails with a  
specific errno it stops trying to use it. Maybe it hits that condition  
at some point. Or maybe the code just isn't called for some reason, I  
don't really know..

On Oct 9, 2008, at 6:45 PM, Stewart Dean wrote:

> I have a call open to IBM with their Compiler group on this to see  
> if this can't be fixed right.  A side question: how come is it that  
> this happens when the session starts up and reoccurs periodically  
> for the first day or so...and then not again unless and until those  
> imap process sessions are closed out
>
>
> Timo Sirainen wrote:
>> On Fri, 2008-10-03 at 14:33 -0400, Stewart Dean wrote:
>>
>>> I am seeing posix_fallocate and file_set_size errmsgs in the mail  
>>> syslog, but
>>> see a pattern:
>>>
>>> 1) They only happen with the /var/spool/mail inbox NOT with any of  
>>> the /home
>>> folders and appear to be happening every 10 minutes from the time  
>>> I started DC
>>> (9AM, 10/1/98) until 11AM, 10/2...and then ceased
>>> The every ten minute message sets looked like this:
>>>  > Oct  1 22:30:31 egg mail:err|error dovecot: IMAP(sdean):  
>>> posix_fallocate()
>>> failed: Resource temporarily unavailable
>>>
>>
>> The main problem here is that posix_fallocate() is broken in your AIX
>> (v1.0 doesn't even try to use it). My previous patch attempted to  
>> make
>> Dovecot detect this and silently fallback to not using it, but
>> apparently it can fail in more ways. I thought about adding another
>> check for EAGAIN, but perhaps posix_fallocate() just returns the
>> previous errno so it can't be checked that way. So I moved the  
>> check to
>> configure instead:
>>
>> http://hg.dovecot.org/dovecot-1.1/rev/12565ef10d1c
>>
>> Alternatively you could just remove HAVE_POSIX_FALLOCATE from  
>> config.h
>> after running configure. Or yet another way would be to try to find  
>> out
>> if it's already been fixed in AIX. This looks related:
>> http://www-01.ibm.com/support/docview.wss?uid=isg1IY77112
>>
>>
>>> 3) However, then there was the following:
>>> a) If I used webmail, which accessed the production server and got  
>>> the indices
>>> on my test server out of sync, I got this error message from in  
>>> the mail syslog
>>> on my test server:
>>>
>>>> Oct  3 12:20:23 egg mail:err|error dovecot: IMAP(sdean): mbox  
>>>> sync: UID inserted
>>>> in the middle of mailbox /var/spool/mail/sdean (648818 > 648046,  
>>>> seq=1153, idx_
>>>> msgs=1187)
>>>>
>>
>> v1.1 also has a bug that can cause this, although normally it  
>> should be
>> visible only when index files aren't being used, or they're out of  
>> sync
>> for some reason. This'll fix it:
>> http://hg.dovecot.org/dovecot-1.1/rev/a5bf7e12f3cc
>>
>>
>>>> Oct  3 12:44:58 egg mail:info dovecot: imap-login: Maximum number  
>>>> of connections
>>>> from user+IP exceeded: user=<sdean>, method=PLAIN,  
>>>> rip=10.20.10.169, lip=192.24
>>>> 6.229.31
>>>>
>>> Turns out I had 10+ sessions, one back from yesterday, so I killed  
>>> them all and
>>> could get mail, but...about six minutes later, I had the two  
>>> posix_fallocate and
>>> file_set_size errmsgs again after not having any for a day.  So  
>>> something about
>>> new connections maybe causes this?
>>>
>>> Any ideas why:
>>> a) I am having leftover IMAP sessions on my test server?  This  
>>> doesn't happen on
>>>   my production DC V1.0 server
>>>
>>
>> Are you sure? Perhaps you just didn't notice them since v1.0 didn't  
>> have
>> any limits to how many were allowed? I think it's more likely that  
>> the
>> client(s) really just left that many connections. So the choices are:
>>
>> a) Increase mail_max_userip_connections setting.
>>
>> b) Figure out where the sessions are from and see if you can do
>> something about them on the client side. In Thunderbird there's a
>> setting which specifies how many connections it can use.
>>

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