Data being backed up seems to be increasing steadily, and there are large changes in space used in the Data volume. How large downloads affect that, and can appear puzzling.
Time Machine
New version improves readability of selected containers, and adds compressed plots that can show months of data in a single view without scrolling.
Over the last 2 months I have been monitoring used and free disk space in my backup storage, and internal SSD. Here are some observations, and a new version of DeltaFree to measure your own.
Changes to keychains, volume structure, Time Machine, Migration Assistant, and the security command tool that have only recently come to light, six months later.
Tahoe 26.4 broke the copying of login keychains. Apple has at last explained how you can copy them successfully, and what backup software needs to do. Explained in full.
For the last 38 days, I have been measuring free and used space in my Mac’s boot container and its backup storage. Here’s what has happened, and how upgrading to macOS 27 changed it.
Although they can only grow in size, and mustn’t be left lying around, snapshots can be very useful, provided you manage them carefully, as described here.
How do you locate part of a document that you removed or changed greatly, and copy that content into the version you’re currently editing? What to do when it’s too much for Undo.
Caching to disk improves performance, but cached data are optional and may be purged when additional free space is needed. This explains how that’s performed by the deleted service.
Major improvements in its plots make this new utility even better for tracking changes in used space, and so forecasting how long backup storage will take to fill.
