Re: [Exim] Performance comparison, LDAP vs. lsearch

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Author: Tony Earnshaw
Date:  
To: exim-users
Subject: Re: [Exim] Performance comparison, LDAP vs. lsearch
tor, 2003-01-23 kl. 07:46 skrev Christian Balzer:

> I'm trying to get a rough, rule of thumb, ballpark figure of where
> the break even point of doing lsearch local file lookups versus ones
> to a remote LDAP database might be.


My two Eurocents' worth, since I'm an avowed LDAP user anyway. The main
reason is, that an LDAP directory is a magic box into which you can
stuff anything about anyone/-thing in an organization once and for all
and administer it centrally. You can not only incorporate al you'd
normally find in a NIS+ database, but much more.

1: I use Exim 4 tcp-based ldaps search/retrieve for users, passwords,
groups, forwarding, aliases etc. I've noticed (is in the spec too) that
the first search of a session is s l o w , second and subsequent are
lightning fast. Not only Exim but also (Openldap 2.1.10) LDAP cache the
results. Moreover, LDAP search attributes can be indexed for faster
access.

2: Remote LDAP directories, or relevant parts of the tree, can be
replicated locally on your mail server for faster access.

3: If you implement point 2, you can use ldapi with Exim 4 with Unix
socket LDAP connections (Openldap), thus avoiding use of tcp altogether.

4: If you don't want to use LDAP or SQL, you can still use dbm databases
with Exim, which are indexed and a lot faster than linear lsearch
searches.

My main argument for LDAP is ease of central administration, with GUI
administration, if you want it.

Best,

Tony

--

Tony Earnshaw

When all's said and done ...
there's nothing left to say or do.

e-post:        tonni@???
www:        http://www.billy.demon.nl