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Druva Documentation

App aware T-Log backup fails with the VMware27 error

 

Problem description

  • App aware T-Log backups fails with the VMware 27 error.
  • Druva Phoenix tracks the LSN value of the transaction logs till the point it has been backed up.
  • In the next attempt, Phoenix attempts to read the SQL Transaction Log on the Server and compares the LSN value.
  • The LSN value picked up from the SQL should be the first LSN written from the moment of the last transaction log backup.
  • The log chain should be consistent for all the  Point-in-Time restore attempts made in the future to ensure consistent data.

Cause

This issue occurs if the log chain is broken.

Traceback

  1. Obtain job logs using the instructions provided in the article
  2. Extract the logs and go to Phoenix<YYYYMMDD>_<timestamp>.log file to view the below traceback in the logs.

[2020-03-13 15:49:43,965] [ERROR] Error <class 'inSyncLib.inSyncError.SyncError'>:Detected chain break for [DB_Name] (#10001001b) (Error Code : VMWARE27). Traceback -Traceback (most recent call last):
File "agents/vmware/appaware_sql_tl_backup_restore.py", line 383, in upload_trans_log_file 
SyncError: Detected chain break for [DB_Name] (#10001001b) (Error Code : VMWARE27)[2020-03-13 15:49:43,965] [ERROR] Error in Uploading Log Files to Storage. : Detected chain break for [DB_Name] (#10001001b) (Error Code : VMWARE27)
[2020-03-13 15:49:44,019] [WARNING] Error occurred while taking SQL TL backup 4295032853 Detected chain break for [DB_Name] (#10001001b) (Error Code : VMWARE27): 10.80.30.24.

Resolution

The VMware App aware feature has intelligence embedded that performs a full backup of the server automatically when T-Log backup fails. This resets the LSN value and the T-Log backups succeed.

It is recommended to verify if there are any backups from either using the SQL native tool or using a third party backup vendor product. If confirmed, disable the non-Druva Phoenix backup as that can cause the Log chain to break.