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SQL TLOG backup failure with exit code SQL8 for Windows 2008 R2 SP2 server

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Problem description

LOG backup fails with exit code SQL8.


This issue arises because of faulty msado15.dll. This is a known issue with Windows 2008 R2 SP2 OS. However, it is advised to verify the behavior from the traceback.


  1. Download the job logs. For more information, see Logs.
  2.  Extract the logs and navigate to file Phoenix<YYYY/MM/DD>-<timestamp>.log and verify the following traceback in the logs.

    [2020-06-09 10:58:58,177] [INFO] <_MainThread(MainThread)> Creating and opening virtual device for db[MEMSERVER-DSQL:model] backup

    [2020-06-09 10:59:28,190] [ERROR] <_MainThread(MainThread)> SqlStream::open_vdi_handle() vdilib error occured: ADODB.Connection CreateInstance failed

    [2020-06-09 10:59:28,190] [ERROR] <_MainThread(MainThread)> Error <class 'vdilib.SqlException'>:ADODB.Connection CreateInstance failed. Traceback -Traceback (most recent call last):

      File "agents\sqlserver\VssHelper.pyc", line 52, in open_vdi_handle

      File "agents\sqlserver\VdiHelper.pyc", line 103, in open

      File "vdilib.pyx", line 177, in vdilib.PyVdiBackup.PyMountAndTransfer (vdilib_pyx.cpp:2502)

      File "vdilib.pyx", line 206, in vdilib.PyVdiBackup.PyCheckError (vdilib_pyx.cpp:2953)

    SqlException: ADODB.Connection CreateInstance failed


    [2020-06-09 11:12:30,164] [ERROR] <_MainThread(MainThread)> SqlAgent :SQL backup failed: ADODB.Connection CreateInstance failed (#100030008) (Error Code : SQL8)

    [2020-06-09 11:12:30,164] [ERROR] <_MainThread(MainThread)> Error <class 'inSyncLib.inSyncError.SyncError'>:ADODB.Connection CreateInstance failed (#100030008) (Error Code : SQL8). Traceback -Traceback (most recent call last):

      File "agentPartnerProcess.pyc", line 85, in _process_request_start

      File "agents\sqlserver\SqlAgent.pyc", line 62, in process_backup_start

      File "agents\sqlserver\SqlBackup.pyc", line 256, in prepare

      File "agents\sqlserver\SqlBackup.pyc", line 234, in __discover_databases

      File "agents\sqlserver\VssHelper.pyc", line 824, in discover_databases

      File "agents\sqlserver\VssHelper.pyc", line 1066, in check_backup_status

    SyncError: ADODB.Connection CreateInstance failed (#100030008) (Error Code : SQL8)


You can resolve the issue using one of the following approaches: 

  • Copy the msado15.dll from a working SQL 2008 R2  server and replace it on the non working SQL server.
  • If you do not have any other windows 2008 R2 server in your environment, then upgrade the OS of the server.

If both the above steps are not feasible then contact Druva support.


After you have resolved the issue,  run one manual backup using the Backup Now option for the database.  After this, the LOG backups will start.