If we spoke about a Linux box, one that prudently ran ZFS, or XFS on top of LVM, it would be possible to make a snapshot before the diffing and sending, so that the snapshot would be indeed point-in-time. IDK if whatever macOS uses for the filesystem supports snapshots.
Otherwise, I think, restic or kopia are better for proper backups, and Syncthing for keeping a mirror copy. But the simplicity of this script in charming.
I’m sure others will chime in that they used hard links like this before then, however as noted in that page, it’s the one that made it popular enough that rsync was updated to support the idea natively.
"borg" has basically solved backups permanently. It's deduplicated, even across snapshots, compressed, and end-to-end encrypted. I'm surprised it's not more well known.
I use bontmia since forever, based on the same rsync feature (link-dest for creating hard links to the unmodified files since the last backup). It also supports backup rotation and I think it's quite solid/reliable after all these years: https://github.com/hcartiaux/bontmia
Used this technique (albeit counter-based, not time-based) successfully for backing up the 2006 World Cup site newsfeed[0] configurations/data. Had 6 rotating backups on two hosts. Never had to use them (as best I remember) but it was definitely comforting to know they were there in case of urgent rollback.
[0] Not strictly the right name but I've forgotten. Y!uk people of that era know what I mean.
This is just half of what Time Machine does. What people are constantly missing is that Apple Time Machine is fast, as it does not need to walk through the whole filesystem to find changed files. Thanks to FSEvents, introduced in Mac OS X Leopard, it knows which directories actually contain changed files and hence usually only needs to check a small fraction of the filesystem. (Not sure if it still works that way after the switch to APFS).
This would of course also be possible on Linux (using *notify), and there are some projects which try to do this, but it's really hard to do it reliably. You might argue that this feature is less important nowadays because NVME SSDs are so fast, but still, I remember very well how astonished I was that creating a new time machine snapshot on OS X Leopard took mere seconds.
I remember doing my own backups with rsync a super long time ago! It worked pretty well, but it didn't have compression, encryption, desktop integration, or deduplication, and adding anything would be one more script to maintain.
Now I use Kopia, no real complaints there. I used to use Borg but until recently it needed some fussy extra community package to work on Synology.
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[ 2.7 ms ] story [ 42.5 ms ] threadAnyone have a good script for macOS triggered by launchd, ideally something that uses FSEvents to check for directory changes?
Otherwise, I think, restic or kopia are better for proper backups, and Syncthing for keeping a mirror copy. But the simplicity of this script in charming.
I’m sure others will chime in that they used hard links like this before then, however as noted in that page, it’s the one that made it popular enough that rsync was updated to support the idea natively.
https://github.com/laurent22/rsync-time-backup
I did the same thing, but with a more detailed writeup, in 2009: https://nuxx.net/blog/2009/12/06/time-machine-for-freebsd/
It was really handy, but I now use borg as it just works better.
I know some folks that have been using that for a very long time as well.
TM integration is just so convenient...
[0] Not strictly the right name but I've forgotten. Y!uk people of that era know what I mean.
[1] https://github.com/linuxmint/timeshift
This would of course also be possible on Linux (using *notify), and there are some projects which try to do this, but it's really hard to do it reliably. You might argue that this feature is less important nowadays because NVME SSDs are so fast, but still, I remember very well how astonished I was that creating a new time machine snapshot on OS X Leopard took mere seconds.
Now I use Kopia, no real complaints there. I used to use Borg but until recently it needed some fussy extra community package to work on Synology.