... Who's had any major issues with it working at all?
...
Useful but beware.
It worked well in Mavericks, for Yosemite it was rewritten - now full of errors. A sample of these:
Critical, both introduced in Yosemite
C1. If you use it to backup an external drive, and your TM drive has less free space than data already backed up from your external, dont let TM run while the drive is dismounted
- on the TM run following remount old backups will be unnecessarily deleted
- at the extreme you may loose all your backups
- Mavericks would scan the drive, Yosemite does a very crude, very wrong calculation
C2. If there is a large (typically multi-GB) file copy in progress when the TM backup starts, it may not backup the whole file, just the amount already written when the backup starts. Mavericks TM would continue running and backup the whole file
Less important
L1. Doesnt do hourly backups, starts a backup an hour after the previous finished, so if a backup runs for a long time, you may be more exposed than you think
L2. Includes padding in its space requirement calculations
- Padding no longer required as TM no longer tries to backup up files that have changed during the backup
- At the margin, if your TM disk is nearly full can result in backups being deleted when they need not be
So whats
S1. Time of next backup in Preferences is often wrong, it assumes that the hour is measured from the start of the backup, not the end - see L1 above
S2. Lots of pointless messages in the logs, such as these:
- <Date and Time> com.apple.prefs.backup.remoteservice[2788]: Attempt to use XPC with a MachService that has HideUntilCheckIn set. This will result in unpredictable behavior: com.apple.backupd.status.xpc
- <Date and Time> com.apple.backupd-helper[46]: Attempt to use XPC with a MachService that has HideUntilCheckIn set. This will result in unpredictable behavior: com.apple.backupd.status.xpc
- <Date and Time> com.apple.xpc.launchd[1]: (com.apple.backupd-auto) This service is defined to be constantly running and is inherently inefficient.
- <Date and Time> com.apple.xpc.launchd[1]: (com.apple.backupd-status) The HideUntilCheckIn property is an architectural performance issue. Please transition away from it.