coexist 10gR2 and 11gR2 RAC db on the same cluster.. stumbling blocks

Due to project/application requirements we had to create a new 10gR2 database on a 11gR2 cluster. These are the high level steps that were attempted to complete this effort.

1. Install 11gR2 Grid Infrastructure
2. Create all ASM diskgroups using asmca
3. Install 11gR2 database binaries
4. Create the 11gR2 database using dbca from the 11gR2 DB home
5. Install 10gR2 database binaries
6. Create 10gR2 database using dbca from the 10gR2 DB home

Once all the prerequisites are met, 11gR2 installation is a very smooth process. Everything goes so smooth. some of us who have worked the some of the true clustered database solutions such as Rdb on VMS clusters (many of you don’t even know that Oracle owns another database called Oracle Rdb.  Oracle acquired this excellent database from Digital Equipment Corporation a.k.a DEC around 1992 and surprisingly Oracle Rdb is used by many customers even today to manage their VLDB systems), Oracle Parallel Servers (OPS) and then most recently with 9iR2 RAC, would remember how difficult it was to complete the installation. Oracle has come a long way in streamlining this process. Its so easy and the entire 11gR2 RAC configuration can be completed with little or no effort in less than 1 hour.

Once the 11gR2 environment as up and running, the next step was to configure the 10gR2 RAC database on the same cluster. We first installed the 10gR2 binaries. runInstaller was able to see that there was a cluster already installed. During the verification step, installer complained of an incompatible version of clusterware  on the server.  We ignored the error and moved on. Binaries installed successfully on all nodes in the cluster.  After installed 10.2.0.1 we complete the upgrade to 10.2.0.4

Note: When 10gR2 installer was available 11g was not, then how can it be aware of a higher version. Higher versions are almost always compatible with the lower versions.  With this idea we moved on.

Stumbling Block I

Next step was to configure the database using dbca. Its important to install the dbca from the 10gR2 /bin directory.  we noticed that the intro screen was different, it did not show the choices we normally see in a clustered database installation.  We did not get the choice to select between creating a ‘RAC’ database or a ‘single instance database’.  This indicated that something was wrong. Why did the installer see that there was a clusterware already there and this is a RAC implementation.  Why not dbca?  Searching through Oracle documentation I found this note.

“When Oracle Database version 10.x or 11x is installed on a new Oracle grid infrastructure for a cluster configuration, it is configured for dynamic cluster configuration, in which some or all IP addresses are provisionally assigned, and other cluster identification information is dynamic. This configuration is incompatible with older database releases, which require fixed addresses and configuration.

You can change the nodes where you want to run the older database to create a persistent configuration. Creating a persistent configuration for a node is called pinning a node.”

We can check if the nodes are pinned using olsnodes command. You have a new switch in 11gR2 that lists the pinned status for a node. 

[prddb1] olsnodes -h
Usage: olsnodes [ [-n] [-i] [-s] [-t] [<node> | -l [-p]] | [-c] ] [-g] [-v]
        where
                -n print node number with the node name
                -p print private interconnect address for the local node
                -i print virtual IP address with the node name
                <node> print information for the specified node
                -l print information for the local node
                -s print node status – active or inactive
                -t print node type – pinned or unpinned
                -g turn on logging
                -v Run in debug mode; use at direction of Oracle Support only.
                -c print clusterware name

[prddb1] olsnodes -t
prddb1     Unpinned
prddb2     Unpinned
prddb3     Unpinned

Pinning of a node is done using the crsctl utility.  crsctl and olsnodes are both located in $GRID_HOME/bin directory.

crsctl pin css –n prddb1

check if they are pinned

[prddb1] olsnodes -t
prddb1     Pinned
prddb2     Pinned
prddb3     Pinned

Stumbling Block II

dbca was now able to see the RAC cluster and we continued.  Ran into the second stumbling block after selecting ASM as the storage manager. “ASM instance not found .. press ok to configure ASM” 

In  11gR2 listeners are driven by the SCAN feature, meaning there is one SCAN listener for each SCAN IP defined in the DNS server. Apart from the three scan listeners, there is a parent SCAN listener that listens on the various database services and connections. Listener service is named as LISTENER in 11gR2 however called LISTENER_<HOSTNAME> in Oracle 10gR2. the dbca log files located in $ORACLE_HOME/cfgtools/dbca/trace.log showed the following entries..

[AWT-EventQueue-0] [11:7:53:935] [NetworkUtilsOPS.getLocalListenerProperties:912] localNode=prddb1, localNodeVIP=prddb1-vip
[AWT-EventQueue-0] [11:7:53:935] [NetworkUtilsOPS.getLocalListenerProperties:913] local listener name = LISTENER_prddb1
[AWT-EventQueue-0] [11:7:53:939] [NetworkUtilsOPS.getLocalListenerProperties:923] No endpoint found for listener name=LISTENER_prddb1
[AWT-EventQueue-0] [11:7:53:939] [ASMAttributes.getConnection:209] getting port using fallback…
[AWT-EventQueue-0] [11:7:53:940] [ASMInstanceRAC.validateASM:609] oracle.sysman.assistants.util.CommonUtils.getListenerProperties(CommonUtils.java:455)

Metalink describes this error and suggests that we use the LISTENER name that is currently configured during database creation.  Well this also did not help.

The workaround was to add the qualified listener to the listener.ora file and to reload the listener.

Stumbling Block III

The listener fix got us through the ASM configuration and database creation. Hoping that is all the issues we could potentially run into we just moved ahead and defined database services as part of the database creation process.

Our next encounter was with the instance /database/services startup process. dbca failed with errors unable to start database, instance and database services. The entries made it to the OCR file as was evident from the crsstat output. However they would not start?  As the obvious step was to check if these resources are registered with the OCR, we checked the status of the database using srvctl

srvctl status database –d  <dbname>  there was no output. How could this be, the crsstat showed the entries but the srvctl gave no results to the check. 

Next step was to take a dump of the OCR file and see if the entries was really in it, found the entries. After considerable research determined that the entire format and structure, syntax of the srvctl utility in 11gR2 is different compared to 10gR2. Tried the srvctl utility from 10gR2 home and it did the trick

We have both 11gR2 and 10gR2 RAC on a 11gR2 clusterware/Grid Infrastructure cluster.  Both using ASM, 11gR2

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