Microsoft® Lync® Server 2013 Unleashed Second Edition

Virtual Disk Types—Fixed, Dynamic, and Pass-through

When you are creating a virtual machine, options exist to create a hard disk for the VM as a fixed size or dynamically expanding. In VMware, the dynamically expanding disk is referred to as thin provisioning. The difference is that with a fixed-size disk, the space allocated to a virtual machine is immediately accounted for on the host operating system disk volume. For instance, if the host has 500GB of free disk space and a 100GB fixed-size disk is created, the host reflects 400GB of free space. Dynamically expanding disks differ in that a maximum size is specified that the disk can grow to, but the space is not immediately consumed. Continuing the previous example, the virtual machine still ...