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Re: High availability

Buchan Milne wrote:
On Sunday 12 August 2007 19:51:39 Dmitriy Kirhlarov wrote:
Taymour A. El Erian wrote:

I have been searching for a long time to find a solution to give me
high availability on the writing. We have 2 ldap servers running as
multi master (I know it is not considered a good thing and it is very
old 2.0.x), this way if one is down the other will accept writes
(add/modify/delete). If we do the normal single master multiple
slaves, we will get more performance and high availability for reads
but if the master is down no updates. Also, we can not separate writes
from reads and we can not use referrals (not all applications we have
can chase referrals). I though of having a standby master and use
heartbeat but it doesnt look like a stable solution, any ideas ? maybe
shared disk ?
For openldap 2.{2,3}.x you can use ggated+gmirror+carp (on freebsd) or
heartbeat + mirror with drdb (on linux). It should work.

Or any clustering system using shared storage. For example, I have a cluster running RHEL3 with Red Hat Cluster Suite on (shared) Fibre-attached storage.

In the end, there isn't that much that is specific to OpenLDAP (e.g. most clustering solutions provide support for MySQL, the only difference is which init script the clustering middleware uses to start/stop the service).

Have you tried RH cluster suite with OpenLDAP, I couldn't find any documentation for that.
For openldap 2.4 two-node multi-master solution declared, afaik, but
currently 2.4 is alpha.

But, for some applications (which just like to assume that one IP address will always have the master), you may still need a load balancer or clustering software to manage a virtual IP address to get the HA part ...


Taymour A El Erian
System Division Manager
TE Data
E-mail: taymour.elerian@tedata.net
Web:     www.tedata.net
Tel:    +(202)-33320700
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Ext:    1101