timeshift with btrfs: am I doing it right?
timeshift with btrfs: am I doing it right?
Hello! I just set up timeshift on my EndeavourOS pc, but this time I chose BTRFS instead of rsync. I currently decided to store the snapshot on the same hard drive of my installation because, well, it's my only one. during the setup, it only asked me if I wanted to include the @home or not. using rsync, instead, it asked for a bunch of locations, and I could choose to include only dotfile, everything, nothing,... is this normal?
also, the snapshot took like... 1 second? with rsync it may take up to 5 minutes... is this normal? or am I backupping fried air?
Creating a snapshot is not the backup itself. It is basically freezing the current state of your files from this point on and then remembering what has chanced compared to the snapshot. So yes, it is normal that this takes no time since nothing is copied on your hard drive. If you want to backup the snapshot you need to make an actual backup of it. This is possible with btrfs. But since I haven’t done it yet, I can’t tell you the exact command.
https://github.com/digint/btrbk
Is the best tool for automating btrfs snapshots and backups.
How does it compare to snapper? It seems like they do basically the same thing
so it is a completely different process than with rsync... I always thought of the two ways are pretty similar
Copy on write is the difference. As I understand it, a btrfs snapshot takes no space when it's created (beyond the file system record). The filesystem is always writing changes to file chunks as a new copy of the chunk, which is then recorded as a replacement of the old chunk (which is still present on-disk). So a snapshot tracks all of these later changes, and the file system keeps the old file chunks preserved as long as you keep the snapshot. That's why you can mount a btrfs snapshot. It just shows you the volume through the lens of all of these saved changes.
When you delete a snapshot you are then marking these preserved chunks as free space. So that is also quick.
Yep, you're doing it right... or at least that's how I do it as well, lol 😂.
A snapshot is exactly that, a snapshot. It doesn't take forever to create, like with rsync, it litelarly takes a second, even on very old rigs (775 or even older). It's basically a snapshot of what the current drive holds. If a file changes (gets added, removed, whatever), the snapshot grows cuz it needs to hold the older versions of the files (the ones saved at the time of the snapshot).
This might not be exactly how snapshots work in BTRFS, but this is what I gathered from using it with snapshots enabled. The older the snapshot, the larger the size of the snapshot (takes way more room cuz more changes have occured).
Also, it's wise to set up daily, weekly and monthly snapshots. I have it set up to hold 5 or 6 (can't really remember now) daily snapshots, 4 weekly and 2 montly. So basically, I can go back in time for a max of 2 months. I was thinking or raising the montly snapshots to 3 or 4, but I'm still not sure. Still, I wouldn't go lower than 2.
Also, it’s wise to set up daily, weekly and monthly snapshots
wouldn't this take a lot of disk space?
Nah, I got it set up on a P4 with a 20GB drive, takes about 2 or 3GB. As time progresses, older snapshots get deleted automatically by Timeshift 😉. So, say you got 4 daily set up, 4 weekly and 2 montly. Only the last 4 daily, 4 weekly and 2 monthly stay, the rest are deleted as new snapshots are created. That's the while point of having this setup, so you can go back in time, but you decide how long.
Depends on how much you change per time unit.
I take full system backups every three hours, but the backups are thinned so that there are previous 24 hourly ones, previous n daily ones, previous m monthly ones, etc. Similar approach can be used with snapshots.
I don't currently use snapshots—I don't run btrfs anymore—but when I did, I did a snapshot every hour and kept them for 24 hours. But then I backed up the latest snapshot, which gives consistent backups, versus regular backups where files can change while you're doing them. I'm nowadays using bcachefs, but I don't quite trust its snapshots yet so I haven't started using them ;).
Depends on your needs and if you want to include changes made to documents in home for example while you work during the day. For me the OS just does snapshotting when packages are updated so I can rollback if something breaks. The rest I do normal backups. because snapshotting is not backup if its on the same machine. Btrfs Send will let you push a snapshot elsrwhere though.
"I currently decided to store the snapshot on the same hard drive of my installation"
That wont do you any good if you get a harddrive crash or need to reinstall. The way i would do it is to make snapshots on a USB and also keep another liveISO USB. That way i can reinstall, then just use timeshift to restore.
I'll definitely have to procurate me a dedicated usb flash!
thats normal. Btrfs only saves a copy of the files once you change them afaik