Optimizing 5.0 to 6.0 LDAP upgrade

 - This article is a Work in Progress, and may be unfinished or missing sections.

LDAP customization

Pre-upgrade tuning

When upgrading from ZCS 5.0.x to ZCS 6.0.x, the LDAP database is exported and then re-imported as the OpenLDAP and underlying database software have changed versions, requiring that this be done. It is possible to optimize this process by increasing the resources available to OpenLDAP to perform this task before starting the upgrade. The primary way of doing this is to increase the number of threads slapadd can have available to it for indexing while importing the new database. To modify the default value from 1 to the number of real cores on your server, do the following. This example assumes you have 8 real cores available (4 dual core cpus, for example):

#Install 6.0 software only
./install.sh -s
# When this finishes, we want to update the olcToolThreads value
cd /opt/zimbra/openldap/etc/openldap/config
# Edit cn=config.ldif, and replace the value for olcToolThreads
olcToolThreads: 8

You will also want to ensure you have a correctly customized DB_CONFIG file. It is advised to have this configured pre-upgrade. This is documented at Managing_Customized_BDB_configurations

If you have a particularly large database, you will also want to pre-set the cachesize values so that when slapd starts up, it'll be able to function well. In this example, we'll update for a database with 500,000 entries.

#Install 6.0 software only
./install.sh -s
# When this finishes, we want to update the various cachesize values
cd /opt/zimbra/openldap/etc/openldap/config/cn\=config
# Edit olcDatabase\=\{2\}hdb.ldif
olcDbCacheSize: 500000
olcDbIDLcacheSize: 500000
olcDbCacheFree: 1000
olcDbDNcacheSize: 1000000

Extra schema migration

If you have used additional schema outside of the schema shipped with ZCS, please see http://wiki.zimbra.com/index.php?title=Installing_custom_ldap_schema_6.0

After you are complete, as root run:

/opt/zimbra/libexec/zmsetup.pl

to start the upgrade.