I am going to try and explain this the best I can.  Something our Database Administrators have noticed here recently with their SQL server backups on SQL servers that are VMware guests.

The DBA's have nightly maintenance jobs that run on the SQL servers, one of the steps of the job is to backup the database.  For the most part the nightly maintenance jobs run at 8:00pm.  I have Avamar backups configured to occur at midnight each night, issue at hand is dealing with the SQL Servers that are VMware guests.  What the DBA's are seeing is when the Avamar backups run, they are seeing in the SQL Server logs a SQL server backup occurs.  In turn this clears out the restore chain of the SQL server transaction logs.  They are seeing that the backups are occurring through a virtual device shown in a copy of one of the SQL Server log event entry.

Date                      12/2/2014 1:03:07 AM
Log                         SQL Server (Current - 11/26/2014 2:07:00 PM)

Source                  Backup

Message
Database backed up. Database: master, creation date(time): 2014/11/19(12:04:50), pages dumped: 466, first LSN: 361:383:70, last LSN: 361:415:1, number of dump devices: 1, device information: (FILE=1, TYPE=VIRTUAL_DEVICE: {'{7C967A3D-0809-4DFF-B9E2-16CB8829D2B4}13'}). This is an informational message only. No user action is required

It this wasn't happening, our DBA's should be able to see the backup that is performed at 8:00pm, and then every 5 minutes of transaction logs up until 7:59pm the next night.  And when I state the DBA's should see the backup that is performed at 8:00pm, I am talking about in SQL server management console.  Since for some reason the Avamar backups that I have occurring at midnight, the DBA's can see the backup performed at 8:00pm and up until 11:59pm, at an internal of every 5 minutes.  Once the Avamar VMware backups run, SQL see's this as a SQL server backup and then clears the previous transaction log backups and then only the transaction logs after midnight are available.

All I have configured in the dataset to use on the VMware machines is the Linux VMware Image and Windows VMware plugins.  The avamar agent is NOT install on these machines.  For some other functionality I will be later on.

I think what is happening is since VMware backups also use the VSS service running on the guest, a quiesce is getting requested and any VSS aware applications running on that server, such as SQL server, is seeing this and quiescing.  In turn breaking the restore chain in SQL server.   But from what I can tell there are no settings to change on the plug-in's to configure the quiesce options.

From the EMC Avamar 7.0 for VMware User Guide, on page 21 it talks about quiescing and states the different types of quiescing, but Avamar doesn't provide any additional quescing other than what is provided by VMware Data Recovery.

I am running Avamar 7.1.0-370

Any thoughts, experience on this?  I would I am not the only one who has seen this, unless I didn't look good I haven't seen this anywhere on the forum.