SAVE BANDWIDTH

Content caching in High Sierra explained

Content caching is, to quote Apple, ‘a macOS service that helps reduce bandwidth and speed up software installation’ across all your core Apple devices: Macs, iOS and Apple TV.

Content is stored – or cached – on one of your Macs, and other devices can pull that content quickly from the local network instead of downloading a fresh copy from the internet. By default, all system updates and App and iBooks Store content are cached, plus there’s an option to include your iCloud content too.

Content caching works best on a Mac that’s connected to your network via Ethernet rather than Wi-Fi. That Mac needs to be switched on and connected to the internet for the feature to work; when it isn’t, your devices will pull the data they need from the internet. The stepby-step guide below reveals the basics to enabling, configuring and disabling the feature.

Beyond the basics

When you embark on setting up the cache, you’ll notice there’s a ‘Share Internet connection’ option – this basically extends the cache (and your Mac’s internet connection) to any iOS device that’s hooked up to the Mac using a USB cable. If your household has lots of Apple devices, and you find one Mac’s bandwidth is getting saturated, you can enable content caching on other Macs too. Devices then intelligently choose which Mac to use to spread the load more evenly.

Go to > System Preferences > Sharing > Content Caching and hold the key: you’ll see the Options button change to Advanced Options. Click this and you’ll see three additional tabs: Clients, Peers and Parents. These allow you to fine-tune your multi-Mac caching setup further. For most people the default settings are fine, but if you’re in a large network, visit bit.ly/contentcaching for a guide to optimising these advanced settings according to your needs.

Though content caching is new to the Sharing pane in macOS High Sierra, the feature has been built in to macOS Server (bit.ly/mfmacserv) for a while. Consequently, even fairly old devices that can’t be upgraded to High Sierra or iOS 11 will benefit from it, as long as they’re running at least iOS 7 or OS X 10.8.2 or later – they’ll automatically detect the cache on your network.