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Re: slapd does not answer in time

--On Thursday, February 21, 2008 3:19 PM +0100 Hans Moser <hans.moser@ofd-sth.niedersachsen.de> wrote:


I have a 4 cpu machine with SLES 9 and OpenLDAP 2.3.35.
This is master to about 65 slaves via syncreplication.

Why do you have 65 slaves? I've yet to really see a need for more than 3-4 slaves unless one has world-wide distributed offices or the like. I would note the following:

(a) there have been a number of significant fixes to sync replication since 2.3.35
(b) syncrepl is highly intensive. delta-syncrepl is not so intensive for ongoing writes
(c) Using a full refresh instead of doing a slapcat of the master/slapadd of the slave (or slapcat of an existing slave to add to a slave) is highly intensive
(d) You make no mention of any tuning you may (or may not) have done, via the DB_CONFIG file for BDB, or the cachesize, idlcachesize, threads, or indexing for slapd, all of which could directly impact the performance of the master.
(e) I generally advise a setup where the master is isolated to only taking writes(*), while letting replicas handle the reads.

(*) - Things that need a guaranteed response should use the master.



Quanah Gibson-Mount
Principal Software Engineer
Zimbra, Inc
Zimbra ::  the leader in open source messaging and collaboration