Database Reference
In-Depth Information
Unsetting Oracle Variables
Ensure the Oracle variables for GRID and RDBMS homes on the local node are unset prior to cluster upgrade.
The following example demonstrates how to unset Oracle variables on the Unix/Linux platforms:
$ unset ORACLE_HOME ORA_CRS_HOME TNS_ADMIN ORA_NLS10 ORACLE_HOME
The
$ORACLE_HOME/bin
path should not be part of the current PATH variable settings on the local node. If it is,
remove the path from the current PATH settings.
Upgrading Flexibility and Restrictions
A few important points to keep in mind before proceeding with an upgrade process:
•
Depending on your needs, you have the flexibility to choose a rolling cluster upgrade or a
non-rolling cluster upgrade method. A rolling upgrade option lets you perform an upgrade
on one node at a time while the other nodes in the cluster go on working, hence requiring less
application downtime for the activity.
•
For a non-rolling cluster upgrade, on the other hand, you will have to stop the cluster stack
completely across all nodes in the cluster. This type of upgrade requires more downtime and a
complete system stop.
•
Clusterware and ASM instance can be upgraded together at once, or you may choose to
perform Clusterware and ASM instance upgrades individually. In this approach, you will have
to upgrade the Clusterware first, after a successful cluster upgrade to 12c, and subsequently
upgrade the ASM instance using the ASM Configuration Assistant tool (
asmca
) from the 12c
Grid Home. Clusterware and ASM instance upgrade together is highly recommended.
•
Before upgrading to 12c, the OCR and voting disks must be migrated from RAW/Block devices
to ASM diskgroup (refer to Chapter 2 to learn how to migrate OCR/voting disks to ASM
diskgroups), as Oracle 12c no longer supports RAW/Block devices. If the OCR/voting disk files
are already on ASM, then you can safely ignore this suggestion.
•
You can't directly upgrade Oracle 10g, 11gR1, or 11gR2 Clusterware to Oracle 12c Flex Cluster.
It can be upgraded only to standard cluster upgrade. To make use of Oracle 12c Flex Cluster
benefits, all nodes in the cluster must be successfully upgraded to 12c before the Flex Cluster
is configured.
•
Only the owner of existing GI software can perform an upgrade to Oracle 12c. You can't use a
different user to upgrade the existing GI home.
•
Upgrades on shared Oracle homes are feasible.
Cluster and ASM Oracle 12c Upgrade Compatibility Matrix
Before upgrading the current environment, review the compatibility matrix to determine whether the current
environment is capable of performing a direct upgrade to Oracle 12c or not. You need to be prepared for situations
such as the current environment not supporting a direct upgrade; how then would you proceed?
Table
13-1
depicts a compatibility matrix for performing direct Oracle 12c upgrades from earlier Oracle versions.
