Track down all those duplicated files, and you could save yourself loads of disk space. Rather, you used to be able to. Why this doesn’t work so well now.
APFS
With a new version of Xcode, I knew that my network backup would take several hours. Then, as it neared its conclusion, disaster struck: the router reset itself and the network share vanished.
How Café and Café are actually different, and only one of those can be a filename in macOS, despite APFS being a non-normalising file system.
Slow performance when backing up to a network share is mainly down to SMB. Without its improvement, Time Machine over a network is still dead in the water.
Provided it doesn’t have to back up large folders containing many small files, Time Machine backing up to APFS on a network share works well.
The first full backup is performed as a manual backup, and largely occurs in file-by-file copying from source to the backup store. It is more efficient than to HFS+, but differences could be less than 10%.
A summary of the known benefits and current limitations of Time Machine backups to APFS, with links to more detailed accounts.
Sparse bundles, sparse files, and sparse matrices explained in a nutshell, and how a sparse bundle could have a band which is a sparse file containing a sparse matrix.
Does Big Sur’s Time Machine preserve sparse files and clones when backing up to APFS volumes?
Adds support for reporting whether a file is a sparse file, or has been cloned, in Big Sur.
The Eclectic Light Company 