Differential updates

Note: The content on this page pertains to Managed Game Server Hosting (Clanforge). If you’re using Game Server Hosting (Multiplay), see the Game Server Hosting (Multiplay) documentation.

A differential game image update (also known as a partial or delta update) is an update that has only the differences between the previous version and the new version. Differential updates are helpful when you want to update the game image version on your fleet machines as quickly as possible. Because differential updates contain less data than full image updates, Game Server Hosting's update orchestration platform can distribute the differential build to your machines faster than a full image update.

Note that differential updates come with some tradeoffs in comparison to full image updates. To understand these tradeoffs, you must first know how the update orchestration platform manages update images.

Each game image starts with a single primary image, which is a full image, and not a differential update. Each time you push out a differential update, Game Server Hosting stores the differential update as a separate archive. For example, if you’ve sent out four differential updates, then you’ll have a primary image plus four differential images. When it's time to install the game image on a new virtual machine, Game Server Hosting combines the primary image with each differential image up to the most recent version.

In the following diagram, a build machine has a primary image (version 1.0.0) and three differential images (versions 1.0.1, 1.0.2, and 1.0.3). When installing image version 1.0.3 on a machine in this example, Game Server Hosting combines the primary image 1.0.0 with differential images 1.0.1, 1.0.2, and 1.0.3. If the primary image is 5 GB and each differential update is 1 GB, then the total size of the game image will be 9 GB.

Distributing differential updates to a fleet.

Over time, the differential image updates can add up, and you can find yourself with a large game image size. You can prevent your images from becoming too large by periodically releasing a full image update. This technique is called “rolling up your game image.”