The content cache service allows organizations to store downloaded applications and system updates for distribution to client devices across LANs while minimizing the impact across the WAN connection.
It's no secret that all devices require updates in order to ensure that endpoints are protected from the latest known attacks, keeping data safeguarded from external threats. This applies to patches that keep both applications and the underlying operating system, up-to-date with the most recent secure and stable code.
Patching modern devices in a timely manner is not without its own unique challenges. Chief among them depends on the number of clients on the network, the total combined file size of the updates required to bring a device into compliance, and the WAN speeds used to download said updates from Apple's update servers.
The resulting task is further complicated by Apple's ever-increasing presence on corporate networks and the influx of personal devices communicating alongside enterprise-managed ones—this means that bandwidth usage could double, triple, or even quadruple the overall network utilization. This can unfortunately result in added expenses and/or degraded performance for all users on the network.
The good news is that Apple has already provided a holistic solution in the form of the content cache service that works its magic by registering itself with Apple's update servers and downloading the content requested on behalf of the clients on the network. It then stores this content on the server's local drive in a designated directory that is protected against access by way of encryption using a key known only to macOS.
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Apple's content cache service—previously only found in macOS Server—is now available to any device and may be enabled on multiple devices to provide redundancy in the form of fail-over or round-robin configuration, serving cached content whenever client devices make the request. This allows for a dramatic reduction in bandwidth utilization overall by containing update traffic to the internal network, which simultaneously optimizes network utilization while drastically cutting down the time it takes to update devices.
Before diving into how to set up Apple's content cache service, let's take a moment to check the lists of requirements, shall we?
- Apple computer running macOS 10.13.4 or later
- Storage space to store cached content for distribution
- Ethernet connection to network (service will run on wireless, though hard-wired is recommended)
- Switched network
- Broadband internet access (required for devices running content cache service)
- Administrative credentials
How to enable Apple's content cache service
- Log on to the Mac computer with administrative credentials.
- Go to System Preferences | Sharing. Click the padlock and enter admin credentials when prompted to allow for modifying services.
- Check the box next to Content Caching. This will enable the service on the device (Figure A).
With the above settings completed, the cache service will be enabled and run with its default configurations. To further modify its running configuration, look to the steps below to granularly control how the cache server will function.
How to modify the content cache server's settings
1. With the Content Caching service on, select the drop-down menu next to Cache to make the service available to Only Shared Content (1st-party applications and updates for macOS and iOS), Only iCloud Content (files and folders users access regularly), or All Content (enabling both former and latter content types) (Figure B).
2. Clicking the Options button allows admins to modify where the cached content will reside. More specifically, admins can choose to store downloaded content for caching on separate drives (either local or networked) without impacting the local storage drives on the devices, if they wish, by clicking the Edit button on the following window and selecting the drive they wish to utilize instead (Figure C).
3. Admins may control how much storage space is made available to the cache by modifying the Cache Size slider. By default, the slider is set to Unlimited. While macOS does an admirable job of maintaining the cache size so as to not leave the host server without available storage, if you wish to further manage the allotted space, you may do so by adjusting the slider scale to the appropriate storage limit (Figure D).
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