How do I switch from linux-generic to linux-virtual?

Solution 1:

No need to install linux-virtual anymore because it has the same dependencies as linux-generic except the package linux-firmware (compare these: http://packages.ubuntu.com/xenial/linux-virtual, http://packages.ubuntu.com/xenial/linux-generic). Also, see the answer here linux-image-virtual packages empty in 14.04 trusty?. But if you want to use it so that you have less packages installed then do this:

• sudo apt-get install linux-virtual (you've already done that)
• sudo apt-get autoremove --purge linux-generic
• sudo apt-get remove --purge linux-firmware
• sudo update-grub

The main packages linux-image-VERSION-generic and linux-headers-VERSION-generic will be the same.

Solution 2:

Depends on which host you are running your VM, you should maybe folow this MS article for Hyper-V: https://technet.microsoft.com/en-us/library/dn531029.aspx

This enables the possibility to generate an VSS-Snapshot for the Backupsoftware.

Most important are these packages:

apt-get install linux-tools-virtual linux-cloud-tools-virtual