ZFS snapshots not supported in Timeshift

[anaximeno]

Describe the bug
After installing Linux Mint 21 with the ZFS filesystem I noticed that timeshift is not able to take snapshots from it. When opening Timeshift it displays a message that says Live Mode (only recuperation), as if I am using the live USB, even though I have already completely installed mint on my device.

To Reproduce
Steps to reproduce the behavior:

1. Go to timeshift (after installing mint with ZFS) and open it.
2. Error message: Live Mode (only recuperation)

System:

• Linux Mint 21 Vanessa
• Cinnamon 5.4.10
• Timeshift v22.06.5

[KAMI911]

It would be nice to add ZFS support.

[anarcat]

this looks like a duplicate of #25

[hudsantos]

There was a similar issue that once was opened on the original repo (not this fork):

teejee2008/timeshift#529

...that was closed by teejee(timeshift creator), with this message: "ZFS has a weird disk layout that is not supported."

Maximum respect for Tony George, we all have been using his creation for years straight.
Lets just take our time to contribute as we can.

The little I know about ZFS it really differs from filesystems that timeshift has been supporting very well so far.

ZFS is a rock solid stable 20+ years old project, from SUN/ORACLE, but as an option on desktop Linux distros where timeshift is popular is still very recent and because of that, it will probably take some time to see timeshift supporting that new scenario.

I really hope that timeshift, be it the original teejee's or this mint's fork, could support ZFS somehow.

[leigh123linux]

-1 to this unless zfs support gets included in main line kernel.

[KAMI911]

@leigh123linux Ubuntu kernel already support ZFS, and the installer also can install Linux Mint or Ubuntu onto ZFS. Why do mainline kernel matter here?

[sskras]

Ubuntu kernel already support ZFS, and the installer also can install Linux Mint or Ubuntu onto ZFS. Why do mainline kernel matter here?

I second that. I just installed Mint 21 onto ZFS, and it's not there:

Seems like @teejee2008 didn't like notion of the first field in the appropriate /proc/mounts line in the aforementioned issue:

Not sure what does it look like for the root-on-BTRFS.

---

The original repo is archived since Oct 16, 2022, it seems. I guess this means that folks interested in this feature can contribute to this repository now.

[florianschroen]

I would like to see zfs support, too. I can contribute with testing.

I guess, this would be much work. I had a quick look to the source, and saw that this a little bit against / aside the existing logic to guess / detect possible datastores (disks/volumes/filesystems) based on the serving device.

zfs is a whole in one solution for classical tools like lvm (volume management), luks (encryption) and ext/btrfs (filesystems).

backup to a zfs (sub)volume

My case would be backup a luks encrypted root on lvm to a 3-disk zfs-raidz1(Raid5). At my zfs pool are different volumes and subvolumes created for different purposes. Some of them use encryption, others don't.

Keeping this in mind, a user has to make sure prefered backup-volume is already setup and mounted. This applies to zfs backup-sources and -destinations.

A timeshift implementation has to look at the mountpoints of type zfs (grep zfs /proc/mounts), instead/in additon to the device detection.

With this behavior a rsync backup can be realized.

backup/snapshot a zfs (sub)volume

for using timeshift for backing up a zfs (volume) as @sskras mentioned, another mechanism needs to be implemented.

zfs has a snapshot function built in. The technical commands and options for zfs snapshot-management can be found in the zfs-autosnap source (https://github.com/rollcat/zfs-autosnap).

some example output from my system:

# disks and partitions (sdd lvm & sd[efg] for zfs)
$ lsblk
NAME                                           MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sdd                                              8:48   1 119,2G  0 disk
├─sdd1                                           8:49   1 234,3M  0 part
└─sdd2                                           8:50   1   119G  0 part
  ├─ssdVG-root                                 253:0    0    40G  0 lvm
  │ └─root                                     253:1    0    40G  0 crypt /
  ├─ssdVG-boot                                 253:2    0     1G  0 lvm   /boot
sde                                              8:64   0   7,3T  0 disk
└─sde1                                           8:65   0   7,2T  0 part
sdf                                              8:80   0   7,3T  0 disk
└─sdf1                                           8:81   0   7,2T  0 part
sdg                                              8:96   0   7,3T  0 disk
└─sdg1                                           8:97   0   7,2T  0 part

$ zpool status usbpool
  pool: usbpool
 state: ONLINE
  scan: scrub repaired 0B in 14:36:51 with 0 errors on Sun Dec 11 15:00:53 2022
config:

        NAME                              STATE     READ WRITE CKSUM
        usbpool                           ONLINE       0     0     0
          raidz1-0                        ONLINE       0     0     0
            wwn-0x5000c500c6988b98-part1  ONLINE       0     0     0
            wwn-0x5000c500d0142180-part1  ONLINE       0     0     0
            wwn-0x5000c500cf99cd54-part1  ONLINE       0     0     0

errors: No known data errors

# list volumes of zfs pool "usbpool"
$ zfs list -r usbpool
NAME                                     USED  AVAIL     REFER  MOUNTPOINT
usbpool                                 7.11T  7.24T      155K  /usbpool
usbpool/backup                          7.01T  7.24T      341K  /usbpool/backup
usbpool/backup/clonezilla               10.0G  7.24T     10.0G  /usbpool/backup/clonezilla
usbpool/backup/proxmox                  5.82T  7.24T     5.77T  /usbpool/backup/proxmox
usbpool/backup/rsnapshot                1.18T  7.24T     1.14T  /usbpool/backup/rsnapshot

# list snapshots of volume "backup" in zfs pool "usbpool"
$ zfs list -t snapshot usbpool/backup | head
NAME                                                    USED  AVAIL     REFER  MOUNTPOINT
usbpool/backup@zfs-auto-snap_monthly-2022-07-12-0643      0B      -      330K  -
usbpool/backup@zfs-auto-snap_monthly-2022-08-12-0557      0B      -      330K  -
usbpool/backup@zfs-auto-snap_monthly-2022-09-11-0629      0B      -      330K  -
usbpool/backup@zfs-auto-snap_monthly-2022-10-11-0610      0B      -      330K  -
usbpool/backup@zfs-auto-snap_weekly-2022-10-21-0554       0B      -      330K  -
usbpool/backup@autosnap_2022-10-27_11:00:04_monthly       0B      -      330K  -
usbpool/backup@autosnap_2022-10-27_11:00:04_daily         0B      -      330K  -
usbpool/backup@autosnap_2022-10-28_00:00:04_daily         0B      -      330K  -
usbpool/backup@zfs-auto-snap_weekly-2022-10-28-0554       0B      -      330K  -

# list snapshots of sub-volume "backup/rsnapshot" in zfs pool "usbpool"
$ zfs list -t snapshot usbpool/backup/rsnapshot | head
NAME                                                              USED  AVAIL     REFER  MOUNTPOINT
usbpool/backup/rsnapshot@zfs-auto-snap_monthly-2022-07-12-0643   5.34G      -     1.14T  -
usbpool/backup/rsnapshot@zfs-auto-snap_monthly-2022-08-12-0557   4.91G      -     1.14T  -
usbpool/backup/rsnapshot@zfs-auto-snap_monthly-2022-09-11-0629   5.40G      -     1.14T  -
usbpool/backup/rsnapshot@zfs-auto-snap_monthly-2022-10-11-0610   2.90G      -     1.14T  -
usbpool/backup/rsnapshot@zfs-auto-snap_weekly-2022-10-21-0554    68.7M      -     1.14T  -
usbpool/backup/rsnapshot@autosnap_2022-10-27_11:00:03_monthly       0B      -     1.14T  -
usbpool/backup/rsnapshot@autosnap_2022-10-27_11:00:03_daily         0B      -     1.14T  -
usbpool/backup/rsnapshot@autosnap_2022-10-28_00:00:03_daily         0B      -     1.14T  -
usbpool/backup/rsnapshot@zfs-auto-snap_weekly-2022-10-28-0554     852K      -     1.14T  -

# listing/counting snapshots can be done recursive
$ zfs list -t snapshot usbpool/backup | wc -l
174
$ zfs list -r -t snapshot usbpool/backup | wc -l
822
$ zfs list -r -t snapshot usbpool | wc -l
1558

# mounts can be listed via /proc/mounts
$ grep zfs /proc/mounts
usbpool /usbpool zfs rw,xattr,noacl 0 0
usbpool/backup /usbpool/backup zfs rw,xattr,noacl 0 0
usbpool/backup/rsnapshot /usbpool/backup/rsnapshot zfs rw,xattr,posixacl 0 0
usbpool/backup/proxmox /usbpool/backup/proxmox zfs rw,xattr,noacl 0 0
usbpool/backup/clonezilla /usbpool/backup/clonezilla zfs rw,xattr,noacl 0 0

[leigh123linux]

@leigh123linux Ubuntu kernel already support ZFS, and the installer also can install Linux Mint or Ubuntu onto ZFS. Why do mainline kernel matter here?

Because ubuntu drops support for it's stupid ideas.

https://www.phoronix.com/news/Ubuntu-23.04-No-OpenZFS

[anaximeno]

I also wouldn't recommend installing Linux Mint with ZFS, BTRFS is a better option for a lot of reasons.

This YouTube video might be a good reference on the pros and cons of some of the most common Linux filesystems: https://youtu.be/G785-kxFH_M

[sskras]

@leigh123linux commented 3 days ago:

Because ubuntu drops support for it's stupid ideas.

https://www.phoronix.com/news/Ubuntu-23.04-No-OpenZFS

Can we stay only on facts and avoid being subjective? Eg:

Because ubuntu drops support for ZFS.

Thanks in advance:)

[sskras]

@anaximeno commented 3 days ago:

I also wouldn't recommend installing Linux Mint with ZFS, BTRFS is a better option for a lot of reasons.

These reasons doesn't seem to include ability to mount a degraded RAID-1:
https://www.reddit.com/r/btrfs/comments/vf2u17/comment/icuf4ao/

[anaximeno]

These reasons doesn't seem to include ability to mount a degraded RAID-1: https://www.reddit.com/r/btrfs/comments/vf2u17/comment/icuf4ao/

It didn't include it, so thanks; now it does.

[anaximeno]

Let me add one thing I forgot to say in the comment about using BTRFS over ZFS.

BTRFS seems to be a better option for personal computers than ZFS, but this is arguable when talking about servers. The way ZFS uses RAM during its operations could be seen as good or bad depending on the conditions of your computer. From what I noticed it is not the best option when having a lower RAM capacity. BTRFS is far from perfect (there are also problems with RAID-5 and RAID-6 if am remembering it right) but it does have good support from the kernel mainline and it's becoming better and faster in each new release.

Well, this is my subjective opinion based on objective facts, I don't believe there's only one way of doing things, so people should use whatever they find is the best option for them.

[sskras]

It didn't include it, so thanks; now it does.

To me this means that some of your pros are cons for other people (in the context of using BTRFS).
So it looks kind of subjective.

From what I noticed it is not the best option when having a lower RAM capacity.

I haven't been running machine with 512 megs of RAM + ZFS, but some folks were:

@vermaden tweeted on 1:06 AM · Apr 13, 2023:

I used 2 x 2TB ZFS mirror for YEARS with 512 MB of RAM on #FreeBSD and everything went smooth - my uptime was as long as I wanted to - usually ended by need for upgrade.

Just limit ARC size to 128 MB and nothing more needed.

My current 5TB of data backup boxes have 2 GB RAM.

So it's a matter of configuration effort and a performance trade-off, IMO.

[anaximeno]

It didn't include it, so thanks; now it does.

To me this means that some of your pros are cons for other people (in the context of using BTRFS).
So it looks kind of subjective.

No. I do see that as a problem BTRFS has, and as such, I do include it when weighing between BTRFS and ZFS.

From what I noticed it is not the best option when having a lower RAM capacity.

I haven't been running machine with 512 megs of RAM + ZFS, but some folks were:

@vermaden tweeted on 1:06 AM · Apr 13, 2023:

I used 2 x 2TB ZFS mirror for YEARS with 512 MB of RAM on #FreeBSD and everything went smooth - my uptime was as long as I wanted to - usually ended by need for upgrade.

Just limit ARC size to 128 MB and nothing more

My current 5TB of data backup boxes have 2 GB RAM.

So it's a matter of configuration effort and a performance trade-off, IMO.

That's nice, I didn't know you can configure it that way.