Avamar: SQL Backup Operations Randomly Stop Responding, Leaving avsql and avtar Processes Stuck

Summary: During Avamar backups, the process may halt unexpectedly, leaving avsql and avtar threads stuck. The issue is caused by a software glitch in the GetConfiguration function of the Microsoft SQL VDI API used by the Avamar plugin. ...

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Symptoms

Randomly during Avamar backup a customer sees backup stopped responding requiring manual intervention. This behavior is mostly seen during backups of large databases and when multi‑streaming is enabled.

<flag type="pulldown" pidnum="3006" value="4" name="max-parallel" />     <flag type="pulldown" pidnum="3006" value="1024" name="min-snapup-size" />

The same server backup will run successfully the next time and may not exhibit these stop‑responding symptoms again for a while.

During the stop‑responding period, data processing halts until the Virtual Backup Device Interface (VDI) connection times out as per "vditransfertimeoutsecs" settings. In the customer case, the timeout was set to 3 hours, causing a timeout for the avsql_t3 thread.

2019-11-05 19:43:27 avsql Info <42988>: VDC_Complete is not supported by VDI. 2019-11-05 19:43:27 avsql Error <6478>: VDS::Getconfig failed with 'The api was waiting and the timeout interval had elapsed' 2019-11-05 19:43:27 avsql Error <6479>: Timed out. Was Microsoft SQLServer running? 2019/11/06-00:43:27.75200 [avsql_t3] Canceling avtar sub-process ...

Here the avsql_t3 thread is stuck after calling GetConfiguration of the SQL VDI function.

Cause

The issue is caused by a software glitch in the GetConfiguration() component of the Microsoft SQL Virtual Backup Device Interface (VDI) API that the Avamar plugin invokes.

Resolution

  • Contact Avamar Support to obtain the latest information and any available hot‑fixes for the issue.

Affected Products

Avamar
Article Properties
Article Number: 000068644
Article Type: Solution
Last Modified: 09 Sep 2026
Version:  6
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