Does APFS currently support hard disks, Fusion Drives, and other forms of storage beyond SSDs? The devil is in the detail.
HFS+
Buying or replacing external storage for Macs is extremely uncertain at the moment because of issues over APFS. Here’s some guidance for selecting hard disks, for backups and more.
Many files in macOS are more than just their data, and contain metadata in extended attributes. Does macOS know the true size of any file, taking into account those attributes?
Have you been warned not to use extended attributes because they aren’t supported beyond macOS? But they are: here are details of file systems and Cloud services.
General account of xattrs, their storage, types, tools for working with them, and common problems.
Even a lean and simple High Sierra system has many xattrs of many types, and plenty of files still have ‘resource forks’. Plus details of some important xattrs used by Apple’s system files.
They’re almost invisible, but surprisingly widely used. xattrs come in very many different types, and contain valuable information. Here are results from analysing most of a Sierra startup volume.
For now, Time Machine can’t back up to an APFS volume. There are many problems with backing up APFS to HFS+, though. Time Machine needs to be revised.
Troubled at times, we have used Disk Utility through thick and thin. Now it has changed to support APFS, with some weird behaviour.
You may still have plenty of space on your backup volume, but if it has millions of files and hard links from years of backups, it will be very slow. Here’s how to fix that.
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