16
timeshift with btrfs: am I doing it right?
(lemmy.kde.social)
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 20 Jul 2023
16 points (100.0% liked)
Linux
45595 readers
736 users here now
From Wikipedia, the free encyclopedia
Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
Rules
- Posts must be relevant to operating systems running the Linux kernel. GNU/Linux or otherwise.
- No misinformation
- No NSFW content
- No hate speech, bigotry, etc
Related Communities
Community icon by Alpár-Etele Méder, licensed under CC BY 3.0
founded 5 years ago
MODERATORS
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.
wouldn't this take a lot of disk space?
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 ;).
Haven't heard of this FS, so I checked the specs... was actually hoping to see a working RAID5/6 feature, but as it stands now it only supports RAID1/0/10. Too bad, would've considered it as a viable option to mdadm + BTRFS.
It said the code base was build on something stable, but it didn't say what, do you happen to know what FS this project is a fork of?
Currently I'm using bcachefs with LVM (which can do raid, but I currently only have one NVME SSD), though it indeed does have RAID1/0/10 support. But overall I expect it not to not make the same silly default choices as btrfs, such as not being able to start the system if a RAID1 component of your root filesystem is missing. And, supposedly, when the RAID5/6 becomes stable, it won't have the write hole problem.
It's based on bcache :) by the same author, but of course bcache is not really a file system but rather some kind of object storage layer for the purpose of caching slower block devices and absorbing write load.
Bcachefs might be coming soon to the mainline kernel, so that's going to make it a lot easier to try out. Personally however I have lost one bcachefs (that FS was readable, though, and I have good backups), but I have also lost a btrfs before and seen reiserfs bugs, so I don't too heavily count it against it; overall I enjoy its stability when using basic functionality. I haven't dared trying snapshots with it yet..