WinterTroubles wrote:/dev/sda2 is a partition
On a regular non VM install you would usually install to /dev/sda which is the actual hard disk. The MBR does not reside within a partition, but, in a 'file' that sits outside of the partitions that the user creates.
VM != LVM
A virtual machine (VM)
is a simulation of a computer, which enables you to run one OS inside another one, such as Windows inside Linux, Linux inside OS X, or even Linux within Linux.
The Logical Volume Manager (LVM)
is a Linux tool that supplements or replaces regular disk partitions. LVM is much more flexible than regular partitions; it enables you to split filesystems across physical disks, add a large filesystem that's larger than any one chunk of free space (with the cost of fragmenting the filesystem), and so on.
You're right that, on a BIOS-based computer, GRUB's first stage normally resides in the MBR, which exists outside of any partition or filesystem. GRUB also relies on other code that's stored elsewhere, including inside normal filesystems, and that does create certain limitations -- GRUB needs a way to read the filesystem that holds its configuration and support files. GRUB includes a number of drivers to do this. I'm pretty sure that an LVM driver is among those that GRUB provides, but I personally have never tried an installation in which the GRUB files reside inside an LVM. For that matter, most distributions that use LVM rely on a separate /boot partition to hold the kernel and GRUB support files.
In sum, a BIOS-mode GRUB relies on code stored several places, which normally includes both the MBR and files in the Linux /boot directory. The details vary depending on the installation, though.