by Joe Grant (@dba_jedi), Principal Architect

A frequent question that we receive from customers is “do I have to license the DR site?” As with most things in IT, the answer is “it depends.” It depends on how DR is being implemented and what technologies are being used to manage DR. Since maintaining a DR site is a huge expense, it is very understandable that one would not want to license it unless absolutely necessary.

So first off, as a quick review, a software license is required for any server that Oracle software is “installed and/or running” on. There are two additional clauses that potentially add confusion when applying this concept to a DR site. They are:

• Backup rule: Most Oracle contracts (the OLSA) state that a backup may be restored to an unlicensed server in order to test backups. This testing is allowed four times a year for two days each time. The contract does not restrict the location of the unlicensed server, so it could be at either the primary or DR sites, or some other site.

• 10-day rule: This states that an unlicensed server may be used to run a workload from a failed server for up to 10 days per year. There are variations on what is allowed for this rule. Older OLSAs do not restrict the location of the unlicensed server. Newer versions however state that the licensed and unlicensed hosts have to share storage, thus making the remote site option impossible. There are further restrictions (such as only one designated failover server allowed per cluster) so be sure to review the terms of your contract for the 10-day rule.

With Oracle databases, a common option to use for DR is Oracle Data Guard. This works by having a standby database which continually applies archivelogs from the primary database. In this case, an Oracle Database license is required. This clearly falls under the “installed and/or running” clause of the Oracle license agreement. In this case, database software is installed and there is a running database instance. Also, the 10-day rule could not be used here, because the standby instance is running on an ongoing basis.

There are many use cases for Data Guard that do not include a DR site, such as a local standby used in the case of a hardware failure of the primary. In these types of cases, the standby also has to be licensed. Again this comes back to the “installed and/or running” clause.

Possible DR solutions for Oracle databases require a little creativity to save on licensing costs. You need to come up with a functional plan that meets the business requirements, but yet does not include installing or running Oracle software. Some possible options include:

• Simple RMAN backup pieces that are replicated to a remote site
• Certain storage replication configurations
• Certain VMware Site Recovery Manager (SRM) configurations

The contract does not prohibit keeping anything that is considered a backup at a remote DR site. A few things that can be considered a backup are:

• RMAN backup pieces
• Replicated database files (SAN based replication), with no installed Oracle software on the remote side
• Copy of a VM (VMware SRM + SAN based replication), if the VM is not in inventory on the remote side
• A tar file of an Oracle Database home that can be extracted in order to restore the software installation

Depending on what your contract states concerning the 10-day rule, anytime a backup is restored (outside of the testing rule) to an unlicensed server at the DR facility, then a license would be required for the DR servers. If the software can be considered uninstalled at the primary site, for example a destroyed facility, then the license from the primary can be reassigned to the DR site. As stated earlier, older license agreements could also potentially allow the workload to run for 10 days on the unlicensed DR server.

In summary, if there is an Oracle software home and/or a running process on the DR server, then the server would need to be licensed. However depending on requirements, and with a little creativity, there are things that can be done to help minimize, delay, or even potentially eliminate, these costs.