Email Security Virtual Appliance drive resizing.
Stop the virtual appliance using the button in System Host Configuration.

Once stopped edit the ESXI Virtual appliance disk space.
This can be increased but never decreased.

Start the SonicWall Email Security Virtual appliance from within ESXi Console.

When the Virtual appliance is booting it will resize the drive.

Log in and verify on the Reports and Monitoring | Monitoring | System Status page that the Data Drive has been resized.
