Certain VMWare jobs will not run in parallel

Problem

Certain VMWare jobs backed up via the Backup Exec Agent for VMWare Virtual Infrastructure (AVVI) will not run in parallel to ensure the data integrity as recommended by VMWare. 

As example:
If a duplicate job runs, a second duplicate job of the same data will not run in parallel.
The second duplicate job even scheduled to run at the same time, will only start to run once the first duplicate job is finished.

This affects all combinations where the same VMDK is being read/write too as part of the job activity.
Some of these combinations are:
Two duplicate jobs of the same backup set
A duplicate job and an Incremental job

 
Hyper-V jobs are not affected by this and are able to run in parallel.
Remote Agent backups are not affected by this.

Error Message

“Ready; The Hyper-V or VMware backup job cannot run until the related job completes”.

NOTE:
The message in the job status field is currently misleading as it includes Hyper-V. This will be corrected in the future.

Solution

To maintain the high level of data integrity, VMware recommends to open a virtual disk (i.e. for read/write) for one operation at a time.
Backup Exec follows this recommendation. 

This is applicable to GRT and Non-GRT backup / duplicate operation of VMWare Virtual Machines