Here's what NOT to do with snapshots

[jfabernathy]

So I was helping a guy debug some stuff and I thought I'd build up a VM with all the prep work needed to start the debug. This took a couple of hours. Then I manually took a snapshot of @ and @home. I thought that was smart. I could revert back to the post-prep work starting point at anytime.

So the first time I need to revert I did the following:

sudo su -
mount /dev/sda2 /mnt
cd /mnt
mv @ @_bad
mv @home @home_bad
mv @snapshots/root/prep-work-finished @
mv @snapshots/home/prep-work-finished @home
reboot

This worked great the first time, but when I needed to revert the second time, I found I had no prep-work-finished snapshots. Duh! I had moved them out the first time.

What I should have done was:

sudo su -
mount /dev/sda2 /mnt
cd /mnt
mv @ @_bad
mv @home @home_bad
btrfs su sn @snapshots/root/prep-work-finished @
btrfs su sn @snapshots/home/prep-work-finished @home
reboot

[Snowhog]

Yup.

[GreyGeek]

Guilty as well.

That's why I create a snapshot every night and store it in /mnt/snapshots/@yyyymmddhhmm
My script is designed to keep the last 5 snapshots and delete older ones.
I also move my daily snapshot to /backup (an external removable drive) with the "btrfs send -p /mnt/snapshots/@yyyymmdd-1hhmm /mnt/snapshots/@yyyymmddhhmm | btrfs receive /backup"

My backup is a 1TB SSD and with 215GB allocated I am able to save about 30 daily snapshots, so I have plenty of room left.

sudo btrfs fi usage /
Overall:
Device size: 463.51GiB
Device allocated: 215.07GiB
Device unallocated: 248.44GiB
Device missing: 0.00B
Used: 201.45GiB
Free (estimated): 257.46GiB (min: 133.24GiB)
Free (statfs, df): 257.46GiB
Data ratio: 1.00
Metadata ratio: 2.00
Global reserve: 338.69MiB (used: 0.00B)
Multiple profiles: no

Data,single: Size:207.01GiB, Used:197.98GiB (95.64%)
/dev/sda3 207.01GiB

Metadata,DUP: Size:4.00GiB, Used:1.73GiB (43.36%)
/dev/sda3 8.00GiB

System,DUP: Size:32.00MiB, Used:48.00KiB (0.15%)
/dev/sda3 64.00MiB

Unallocated:
/dev/sda3 248.44GiB[/FONT]

[jfabernathy]

The workstation I'm running my test on is using timeshift. But on the VM that contains the actual test I'm using manual snapshots I mention in the first post. I didn't want anything on a timed bases. I have them at different stages of the build so I don't have to start over from the OS install every time it's dies. I just need to remember to snapshot back instead of mv.