Avamar: SQL Cluster Backups Fail Due to Log Gap and Missing sqlmeta.xml

SQL Incremental Backup Failure

• SQL incremental backups for a SQL Cluster or SQL AG fail with the following errors:

Line 542: 2019/12/05-16:49:56.85100 [avsql_assist]  avspawn::run_and_wait back from wait error_num:536870919 wait_error:0
	Line 547: 2019-12-05 17:49:56 avsql Warning <7427>: Error loading SQL metadata
	Line 555: avtar Error <5195>: Path ".system_info\sqlmeta" not found in backup. (Element 'sqlmeta' at position 1 in search path '.system_info\sqlmeta' not found)
	Line 634: 2019-12-05 17:49:57 avsql Error <40418>: Skipping database 'sql-listener\VIEWSQL/viewupdmgr' due to the following reason: A log gap was identified or a full backup was not found.
	Line 755: 2019/12/05-16:50:04.42799 [avsql_assist]  avspawn::run_and_wait back from wait error_num:536870919 wait_error:0
	Line 755: 2019/12/05-16:50:04.42799 [avsql_assist]  avspawn::run_and_wait back from wait error_num:536870919 wait_error:0
	Line 762: 2019-12-05 17:50:04 avsql Warning <7427>: Error loading SQL metadata
	Line 770: avtar Error <5195>: Path ".system_info\sqlmeta" not found in backup. (Element 'sqlmeta' at position 1 in search path '.system_info\sqlmeta' not found)
	Line 849: 2019-12-05 17:50:05 avsql Error <40418>: Skipping database 'sql-listener\VIEWSQL/viewevent' due to the following reason: A log gap was identified or a full backup was not found.

• If the backup label is examined, the following command also returns an error indicating the missing metadata file:

avtar -x --debug --server=<Avamar_server> --id=MCUser --ap=MCUser_password --path=<path_to_client> --labelnum="91631" --noinfo --noconfig ".system_info" --target=c:\temp\ --logfile=c:\temp\system_info.log --internal

Log Gap Root Cause

The log gap occurs because Avamar cannot read the sqlmeta.xml file from previous SQL backups. When the file is missing or unreadable, the backup engine cannot correlate transaction logs, resulting in a “log gap” condition and backup failure.

• Missing sqlmeta.xml prevents reconstruction of the backup timeline.
• Corrupted or inaccessible file leads to inability to locate prior backup metadata.
• Resulting error manifests as “sqlmeta.xml not found” during incremental backup processing.

Troubleshooting Steps

1. Create "c:\temp" if it does not exist, run as admin while cd in the Avamar BIN folder on the primary SQL Node:

   avtar --list --debug --server=<Avamar_server> --id=MCUser --ap=MCUser_password --path=<path_to_client> --labelnum="91631" --noinfo --noconfig --logfile=c:\temp\backup_list.log

   Note: --labelnum="91631" is the backup label number.

2. Check if the sqlmeta.xml file is present in the output from the above command.

   If the file is present, then try the restore of '.system_info' from the backup using below command:

   avtar -x --debug --server=<Avamar_server> --id=MCUser --ap=MCUser_password --path=<path_to_client> --labelnum="91631" --noinfo --noconfig ".system_info" --target=c:\temp\ --logfile=c:\temp\system_info.log --internal

3. If the sqlmeta.xml file does not exist in the backup label (above), try this:

   • Check if there is any sqlmeta.xml file in the cluster/shared var directory, if the file exists then delete or move the file to another location.
   • After deleting/moving the file, perform full backups and then incremental backups.
   • Running full backup followed by incremental backup ensures creation of a new sqlmeta.xml file.