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Re: Fail over

On Wed, Sep 11, 2002 at 09:37:05AM -0600, Banzaitron wrote:
| Can someone in the know comment about multi-master replication?  It
| definitely would be nice to have two LDAPs keeping each other in synch
| (rather than one readonly emergency backup).  Is it available in 2.1.X?
| What steps are involved in implementing it if it is available?
| Thanks,
| Andy

Multimaster involves experimental code that needs some extra work to
enable (i.e. you have to do things *before* configure --enable-multimaster
will work).  Its in 2.0.25, and my memory is that the mailing list archives
(I think development) have notes on how to do it.

I should note that before you do that, look *very* carefully at the
code that is enabled by multimaster (SLAPD_MULTIMASTER tags), because
there are some rather interesting side effects on how multimaster is
currently implemented.

Ryan Moats

| ----- Original Message -----
| From: "Tarassov Vadim" <Vadim.Tarassov@winterthur.ch>
| To: "'Bjørn Ove Grøtan'" <bjorn.grotan@itea.ntnu.no>; "Kristyan Osborne"
| <kris@longhill.brighton-hove.sch.uk>
| Cc: "OpenLDAP (E-mail)" <openldap-software@OpenLDAP.org>
| Sent: Wednesday, September 11, 2002 6:52 AM
| Subject: AW: Fail over
| Hi Bjorn,
| I am not sure that Kristyan is asking about slurpd. Slurpd will update
| replica, it is not substitution for any sort of clustering or so. If master
| is not available, you will not be able update replica anyway, which means
| that you've zero of failover in applications doing lots of updates. The
| better way to achive his goal would be real multi-master replication, but I
| am not sure that it works with recent versions of openldap (2.1.*). There
| were lots of letters around recently about multimaster replication, but up
| to my best knowledge they were related to 2.0.* versions of openldap. People
| were suggesting to use --enable-multimaser or #define SLAPD_MULTIMASTER 1 in
| portable.h. I don't think in 2.1.2 either of them has an effect, in 2.1..4
| #define SLAPD_MULTIMASTER is commented, so perhaps, it would make sense to
| try that multimaster activity with 2.1.4? Well, anyway that's all details. I
| am reading this maillist during last three month and I have not noticed that
| multimaster re!
|  plication is sort of "officially" available feature in openldap, well at
| least people do not really like to talk about it. In such case it probably
| would make more sense to dig in direction of conventional clustering.
| Regards, Vadim Tarassov.
| -----Ursprüngliche Nachricht-----
| Von: Bjørn Ove Grøtan [mailto:bjorn.grotan@itea.ntnu.no]
| Gesendet: Mittwoch, 11. September 2002 14:14
| An: Kristyan Osborne
| Cc: OpenLDAP (E-mail)
| Betreff: Re: Fail over
| Kristyan Osborne:
| > Hi,
| >
| > I'm quite new to openldap so you will have to excuse any stupid questions
| from me.
| >
| > I want to make my ldap server redundant so that if it fails another one
| could take over with no or very little down time.
| >
| > Could someone explain to me how to do this or point me to some
| documentation.
| >
| Browse the list archives for "multi-master" and you can catch the
| documentation
| on Slurpd.
| Regards
| Bjørn Ove Grøtan