Post-failure analysis and reset - SAP HANA on AWS

Post-failure analysis and reset

A review must be conducted after each failure to understand the source of failure as well the reaction of the cluster. In most scenarios, the cluster prevents an application outage. However, a manual action is often required to reset the cluster to a protective state for any subsequent failures.

Checking the Logs

  • For troubleshooting cluster issues, use journalctl to examine both pacemaker and corosync logs:

    # journalctl -u pacemaker -u corosync --since "1 hour ago"
    • Use --since to specify time periods (e.g., "2 hours ago", "today")

    • Add -f to follow logs in real-time

    • Combine with grep for specific searches

  • System messages and resource agent activity can be found in /var/log/messages.

  • For HANA-specific issues, check the HANA trace directory. This can be reached using 'cdtrace' when logged in as <sid>adm. Also consult the DB_<tenantdb> directory within the HANA trace directory.

Cleanup crm status

If failed actions are reported using the crm status command, and if they have already been investigated, then you can clear the reports with the following command.

# crm resource cleanup <resource> <hostname>

Restart failed nodes or pacemaker

It is recommended that failed (or fenced) nodes are not automatically restarted. It gives operators a chance to investigate the failure, and ensure that the cluster doesn’t make assumptions about the state of resources.

You need to restart the instance or the pacemaker service based on your approach.

Further Analysis

For cluster-specific issues, use hb_report to generate a targeted analysis of cluster components across all nodes:

# hb_report -f "YYYY-MM-DD HH:MM:SS" -t "YYYY-MM-DD HH:MM:SS" /tmp/hb_report

For quick analysis of recent events, you can use:

# crm history events # crm history log
  • Both hb_report and crm history commands require passwordless SSH between nodes

  • For more information, see SUSE Documentation - Usage of hb_report for SLES HAE