[Dovecot] Auth Issues - Urgent - Help!

[David Cunningham]

Simply changing auth_cache_size to a non-zero number enables caching, correct?

How big is too big?

Where does it cache it?

Here is what I set:

auth_cache_size = 1048576

I was hoping for 1GB worth of cache.

I have 16GB of memory on the system, so memory is not an issue if it  
stores it in memory as opposed to disk.

Dave

Quoting David Cunningham <davec at mecnet.net>:

> Thank you, I will try the caching.
>
> Dave
>
> Quoting Timo Sirainen <tss at iki.fi>:
>
>> On Wed, 2008-10-08 at 10:48 -0400, David Cunningham wrote:
>>> I agree.  In fact, I may have found a DNS issue that may have been
>>> causing login sessions to hang and thus reach max too quickly.  The
>>> last few hours have been stable.  So, I am keeping my fingers crossed.
>>>
>>> I have also recompiled dovecot and changed the setting in db-ldap.h
>>> that reads:
>>>
>>> #define DB_LDAP_MAX_QUEUE_SIZE 1024
>>>
>>> to
>>>
>>> #define DB_LDAP_MAX_QUEUE_SIZE 8192
>>
>> If you're getting more than 1024 requests queued, something's wrong or
>> you have hundreds or logins per second. Which one is it? (5000 users
>> logging in once per minute is still only 83/sec)
>>
>> The queue keeps increasing if the LDAP server isn't replying to old
>> requests. So have you looked at the LDAP server side if it's running too
>> slow?
>>
>> Anyway two things you could do here:
>>
>> 1) Enable auth cache with large enough size so Dovecot doesn't consult
>> LDAP server nearly as much.
>>
>> 2) Increase the number of auth processes (auth { .. count=5 }), so that
>> you'll use more connections and hopefully the LDAP server likes that
>> better than one connection sending lots of requests. Or maybe not.
>>
>>