Re: [tlug] next meeting

[Masato Taruishi <taru@example.com>]

On Wed, 14 Jan 2004 11:49:05 +0900
Blomberg David <dblomber@example.com> wrote:

> > > > I just joined this mailing list because I'll have a speech about LDAP
> > > > at the next meeting. Unfortunately I'm not good at English, so I'd like
> > > > to say sorry about the speech. 
> > > Does this mean you can explain all the strangness of getting LDAP up and
> > > running correctly :)
> > 
> > I can explain if it's in Japanese :)
> > 
> > I won't speak about getting started LDAP environment, but the syncbackup idea
> > itself because I'd like to practice English before explaining syncabckup to
> > LDAP guys of IETF and because I can't explain the strangeness of getting LDAP up
> > in English. If this topic is not appropriate for tlec metting, I won't have the
> > speech itself.
> We are looking over your web site (A colleague of mine who also works
> Linux and is helping me on a few LDAP issues)  I am a little unclear on
> one matter that does not seem to be addressed on the site ----
> 
> How do you compare to OpenLDAP in multimaster compiled mode??? and what
> advantages do you offer over multimaster as I still need to recompile
> either way :) ???

At first, syncbackup can be used in multimaster environment, too. 
syncbackup is nothing but one way to replicate modifications to other servers.
If we compare multimaster, we should compare it with single-master.

So if we compare syncbackup, we should compare it with slurpd based replication.
This can't guarantee complete consistency between several LDAP servers because
of slurpd design problems itself and also because of asynchronous replication.

One big problem of slurpd is that it doesn't have consistency framework but just
makes reject file. If one modification fails, then all other modifications may
fail because of the previous failure. In addition, slurpd is difficult to setup
slave servers on demand. We must synchronize the initial database of a slave server
and the begging of replication to the server.

In openldap 2.2, it provides syncrepl which supports eventual consistency. This makes
easy to maintain several slave servers, but it's a still asynchronous replication.
If the server is broken before propagating modifications, these modifications which
are not propagated to other servers are lost. syncbackup doesn't conflict with syncrepl.
Actually, syncbackup uses syncrepl internally. syncbackup provides guarantees such that
modifications are actually propagated because syncbackup waits for the success result
from other servers, while syncrepl doesn't, it only sends modifications.

I guess 'multimaster or single-master' is a different topic. Do you want to discuss
about this topic, too?

--- 
Masato Taruishi - VA Linux Systems Japan Inc. <taru@example.com>
                - Debian Project <taru@example.com>
                - Debian JP Project <taru@example.com>