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Re: High CPU usage with syncrepl on 2.26



--On Tuesday, November 08, 2005 11:43 AM -0600 Ben Beuchler <insyte@gmail.com> wrote:

I'm using OpenLDAP 2.26 on Ubuntu linux.   Replication appears to be
working in that when I first fired up the secondary server it pulled
across the full database and if I modify an entry on the primary
server, the modification is properly sync'd to the secondary.
However, if I add a new entry to the primary, the CPU load on the
primary immediately jumps to 100% and stops responding.  As this is a
production server, I haven't been able to wait to see how long this
state lasts.  If I shut down the secondary server and add the new
entry to the primary, it is sync'd as soon as I start the secondary
back up.

This is the syncrepl section from the secondary config:

syncrepl rid=42
        provider=ldaps://ldap.mcad.edu
        type=refreshAndPersist
        searchbase="dc=ldap,dc=mcad,dc=edu"
        filter="(objectclass=*)"
        scope=sub
        updatedn="cn=replicant,dc=bindaccts,dc=ldap,dc=mcad,dc=edu"
        bindmethod=simple
        binddn="cn=syncclient,dc=bindaccts,dc=ldap,dc=mcad,dc=edu"
        credentials=<snip>

And the sessionlog entry from the primary server:

sessionlog 1 100

Any thoughts on why this might be happening?

I'd use OpenLDAP 2.3, where syncrepl was completely rewritten to be more efficient. One of the issues with syncrepl that remains, however, is that it does full entry replacement, rather than delta changes like slurpd does, which does cause a larger hit on the master. OpenLDAP 2.3.12, whenever that gets released, will include support for delta-syncrepl, which works on delta's just like slurpd, and thus is more efficient.

--Quanah


--
Quanah Gibson-Mount
Principal Software Developer
ITSS/Shared Services
Stanford University
GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html

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