Limitations of a Site Aware Disaster Tolerant Architecture

Following is a limitation of SADTA:

•No Support for Arbitrator Nodes

When configuring Metrocluster for applications using CFS sub-clustering storage, no arbitrator nodes must be configured. The Metrocluster, in such configurations, must only use the Quorum Server at a third location to handle network partitions. Additionally, in a cross-subnet environment, appropriate network routes to the Quorum Server at the third location, must be configured on both the site nodes.

Troubleshooting

This section describes the procedures to troubleshoot errors and error messages that occur in a SADTA environment.

This section addresses the following topics:

•Logs and Files

•Cleaning the Site to Restart the Site Controller Package

•Identifying and Cleaning RAC MNP Stack Packages that are Halted

•Understanding Site Controller Package Logs

Logs and Files

This section describes the guidelines to be considered before working with files that need to be configured for SADTA.

Following are some of the guidelines to consider:

•The Site Controller Package control log file can be specified using the attribute script_log_file in the Site Controller Package configuration file.

Serviceguard defaults the Site Controller Package logs to the default log destination. The default log destination for a given Site Controller Package is /var/adm/cmcluster/log <Site_controller_package_name>.log.

•It is recommended that you specify the Site Controller Package log file under the directory specified for the dts/dts/dts_pkg_dir attribute in the Site Controller Package configuration file.

•The Metrocluster storage preparation modules will also log to the Site Controller Package log file.

•The RAC MNP package at each site will log in a file named <RAC MNP package control script file name>.log under its package directory on the site nodes.

•The CFS MP MNP packages will log to a file named /etc/cmcluster/cfs/<CFS MP MNP package name>.log on their corresponding CFS sub-cluster nodes.

•The CVM DG MNP packages will log to a file named /etc/cmcluster/cfs/<CVM DG MNP package name>.log on their corresponding CFS sub-cluster nodes.

•The Site Safety Latch mechanism logs are saved in the/etc/opt/resmon/log/api.log file.

Cleaning the Site to Restart the Site Controller Package

The Site Controller Package startup on a site can fail for various reasons. The Site Safety Latch will be in a special state: INTERMEDIATE. In this state, the Site Controller Package cannot be started from either of the sites. A special tool called cmresetsc is provided to cleanup a site under this condition. This tool will clean the Metrocluster environment in site for the Site Controller Package.

Limitations of a Site Aware Disaster Tolerant Architecture 405