Storage Considerations for Oracle Grid Infrastructure and Oracle RAC

For all installations, you must choose the storage option to use for Oracle Grid Infrastructure (Oracle Clusterware and Oracle ASM), and Oracle Real Application Clusters (Oracle RAC) databases.

Storage Considerations for Oracle Clusterware

Oracle Clusterware voting files are used to monitor cluster node status, and Oracle Cluster Registry (OCR) files contain configuration information about the cluster. You must store Oracle Cluster Registry (OCR) and voting files in Oracle ASM disk groups. You can also store a backup of the OCR file in a disk group. Storage must be shared; any node that does not have access to an absolute majority of voting files (more than half) is restarted.

If you use Oracle ASM disk groups created on Network File System (NFS) for storage, then ensure that you follow the recommendations for mounting NFS described in the topic Guidelines for Configuring Oracle ASM Disk Groups on NFS.

Storage Considerations for Oracle RAC

Oracle ASM is a supported storage option for database and recovery files. For all installations, Oracle recommends that you create at least two separate Oracle ASM disk groups: One for Oracle Database data files, and one for recovery files. Oracle recommends that you place the Oracle Database disk group and the recovery files disk group in separate failure groups.

  • If you do not use Oracle ASM for database files, then Oracle recommends that you place the data files and the Fast Recovery Area in shared storage located outside of the Oracle home, in separate locations, so that a hardware failure does not affect availability.

  • You can choose any combination of the supported storage options for each file type provided that you satisfy all requirements listed for the chosen storage options.

  • If you plan to install an Oracle RAC home on a shared OCFS2 location, then you must upgrade OCFS2 to at least version 1.4.1, which supports shared writable mmaps.

  • To use Oracle ASM with Oracle RAC, and if you are configuring a new Oracle ASM instance, then your system must meet the following conditions:

    • All nodes on the cluster have Oracle Clusterware and Oracle ASM 12c Release 2 (12.2) installed as part of an Oracle Grid Infrastructure for a cluster installation.

    • Any existing Oracle ASM instance on any node in the cluster is shut down.

    • To provide voting file redundancy, one Oracle ASM disk group is sufficient. The Oracle ASM disk group provides three or five copies.

You can use NFS, with or without Direct NFS, to store Oracle Database data files. You cannot use NFS as storage for Oracle Clusterware files.