Alan Blair
Level 1
(9 points)
Q: time machine
After Time Machine finishes backing up my iMac, the words "Cleaning Up" are displayed below the scroll bar that depicts how much of the event has finished. Sometimes this "Cleaning Up" takes several minutes (up to 30 minutes), while other times, it's done after only a few seconds. What is going on behind the scenes when Time Machine is Cleaning Up?
iMac, OS X El Capitan (10.11.6), iMac (24-inch, Early 2009)
BDAqua
Level 10
(123,484 points)
Finishing Backup or Cleaning Up
This is usually done at the end of each backup, but if the Preparing phase determines there isn't enough room for the new backup, it will be done first.
- •On every backup, Time Machine deletes any "expired" backups:
- •Any backup over 24 hours old, keeping only the first backup of each day.
- •Any of those "daily" backups over 30 days old, keeping only the first of the week.
- (Unless it's out of room, Time Machine will only delete 5 expired backups at a time.)
- •If there isn't enough room for the new backup, Time Machine will delete any expired backups first; if that doesn't make enough space, it will then delete the oldest backup(s).
These deletions can be fairly quick, or may take quite a while, depending on how many items are involved. And, the slower the connection to them, the longer it will take -- so if you're backing-up wirelessly, it will take much longer than to an external drive connected by FireWire.
Each deletion is documented in the system.log. You can see or monitor these via the Consoleapplication or via the widget in section #A1.
If you see a message saying "Found partially deleted backup; trying again to delete," the named backup may be damaged -- Time Machine probably tried to delete it earlier, but couldn't. If you see the same one on repeated backups, try deleting it via the Finder. If that doesn't work, try repairingyour backups, per item #A5.
Unless it's out of space, you can cancel a backup in this phase without causing a problem -- Time Machine will "catch up" the necessary deletions on subsequent backups. Cancelling one that's out of room won't cause a serious problem, but it does mean no backup can be made.
(On Snow Leopard or Leopard, when Time Machine is out of room for backups made over a network, this can be extremely slow. Time Machine must "compact" the sparse bundle after each deletion. It's even worse if a "deep traversal" is required, as that is also performed after each one.)
