Time Machine & Local Snapshots

Time machine can keep local snapshots. While this feature is useful if you travel and don’t have access to your Time Capsule, the local snapshots can consume a lot of the local disk space in /.MobileBackups. There is a complex Removal Algorithm for old local snapshots based on the remaining free disk space.

To find out how much space your local snapshots consume (Local Snapshots):

  • Apple-Logo → About This Mac → Further Information → Storage: Backup == Local Snapshot Space
  • Alternatively from commandline:
    test -d /.MobileBackups && du -hcs /.MobileBackups

It is useful to control the behavior of the local snapshots yourself (Controlling Local Snapshots) using tmutil disablelocal and tmutil enablelocal.


Clean Up a Time Capsule Sparse Image

Consider you want to remove a bunch of old updates (i.e. of an old Mac) from your Time Capsule (TC). You could erase the whole disk, but usually this is not what you intend to do. Another alternative is to remove the plain sparse bundle containing the old backups. Removing sparse bundles – in particular for >1TB backups – from a TC can be a pain due to the time consumption. This is a result of the approach to split the backup in ~8MB sized directories. 

In the following I present s fast way to clean your TC.

Preparation:

  1. Mount your TC, become root and do to the folder.
  2. Find your XYZ.sparsebundle

Deletion (you may want to monitor the progress in a 2nd terminal using df -h):

cd ./XYZ.sparsebundle/bands

for a in {0..9} {a..f}; do for b in {0..9} {a..f}; do for c in {0..9} {a..f}; do for d in {0..9} {a..f}; do echo $a$b$c$d && rm -drf $a$b$c$d ;done;done;done;done

for a in {0..9} {a..f}; do for b in {0..9} {a..f}; do for c in {0..9} {a..f}; do echo $a$b$c && rm -drf $a$b$c ;done;done;done

for a in {0..9} {a..f}; do for b in {0..9} {a..f}; do for c in {0..9} {a..f}; do for d in {0..9} {a..f}; do for e in {0..9} {a..f}; do echo $a$b$c$d$e && rm -drf $a$b$c$d$e ;done;done;done;done;done