Azure file system issue

Question

the SAP HANA database server became unavailable due to a local file system issue. Critical directories required for HANA service startup (e.g., /hana/log/DE1) were not visible or mounted, preventing services from starting. Service was restored by re-attaching the affected filesystem via the Azure Portal. Any troubleshooting steps for the issue and a Root Cause Analysis (RCA) to prevent recurrence.

Answer 1

To troubleshoot the issue of the SAP HANA database server becoming unavailable due to a local file system issue, consider the following steps:

1. Check Mount Status: Ensure that the file system is properly mounted. You can verify this by checking the output of the mount command to see if the required directories (e.g., /hana/log/DE1) are listed.
2. Review Logs: Examine the SAP HANA logs for any error messages related to file system access or mounting issues. This can provide insights into what went wrong.
3. Disk Health Check: Perform a health check on the disk where the file system resides to rule out any disk corruption or hardware issues.
4. Permissions Verification: Ensure that the necessary permissions are set correctly on the directories required for the HANA service to start. The root account should have read/write permissions on the mounted file share.
5. Network Connectivity: If the file system is hosted on Azure, check for any network connectivity issues that might prevent access to the file share.
6. Service Dependencies: Verify if there are any dependencies or services that need to be running before the HANA service can start, and ensure they are operational.

Root Cause Analysis (RCA):

• Cause: The unavailability of critical directories was likely due to the file system not being mounted properly or being detached unexpectedly.
• Preventive Measures:
  • Implement monitoring for the file system mount status and set up alerts for any disconnections.
  • Regularly check and maintain the health of the Azure file share and the underlying infrastructure.
  • Consider using Azure Backup to ensure that data can be restored quickly in case of similar issues in the future.

By following these troubleshooting steps and conducting a thorough RCA, you can help prevent recurrence of this issue.