Oracle rolling upgrades Oracle Database Tips by Donald Burleson

A "rolling upgrade" is a zero-downtime method for upgrading the Oracle software. 

Burleson Consulting offer a minimum-downtime and rolling upgrade service.  Just call now to schedule your rolling upgrade.

If you can spare five minutes, there is an alternative to the RAC rolling upgrades.  Oracle Real Application clusters supports rolling upgrades, but it's complex.   

Also see low downtime Oracle upgrade secrets.

As you can imagine, the term rolling upgrade means performing an upgrade to different databases one at a time without stopping the database.  Not just for single instance environments, the rolling upgrade can also be performed on a Real Application Clusters (RAC) environment where different instances of the same database can be upgraded one at a time without shutting everything down.

This is exciting for RAC shops because that generally means that some of the instances will remain available during any outage scheduled for patch upgrades.  The instances are brought down one-by-one, leaving the rest online to do the work.  The Oracle opatch utility allows a patch to be applied successively to each different instance on the cluster.

This can keep scheduled outage time minimal; however, not all patches are eligible for rolling upgrades.  Oracle must certify the patch for a rolling upgrade and rolling patch upgrades for cases where the Oracle home is on a Cluster File System (CFS).  They are also not available for cases where the Oracle home is on shared volumes provided by file servers or NFS-mounted drives.  In all cases of approved rolling upgrade patches, each node must have its own copy of the Oracle Database software.

Situations where rolling upgrades can be certified include the following situations where patches:

• do not affect database contents, including the data dictionary

• are not related to RAC inter-node communication

• are related to client-side tools.  Such tools might include SQL*Plus, Oracle utilities and SQL*Net

• do not change shared database resources.  Such resources might include control files, common header definitions of kernel modules and/or datafile headers.

• are one-off patches.  Rolling upgrades are currently not approved for patch sets.

If you like Oracle tuning, you may enjoy my new book "Oracle Tuning: The Definitive Reference", over 900 pages of BC's favorite tuning tips & scripts.  You can buy it direct from the publisher for 30%-off and get instant access to the code depot of Oracle tuning scripts.