Virtual desktop infrastructure (VDI) operating system boot images are a good use case for FileSnaps. The parts of the boot images that can change are user profile, page files (or swap for UNIX/Linux) and application data. You should separate such data from boot images to minimize unsharing. You should allocate a single extent to the master boot image file.

The following example uses a 4 GB master boot image that has a single extent that will be shared by all snapshots.

  # touch /vdi_images/master_image
  # /opt/VRTS/bin/setext -r 4g -f chgsize /vdi_images/master_image

The master_image file can be presented as a disk device to the virtual machine for installing the operating system. Once the operating system is installed and configured, the file is ready for snapshots.