Btrfs Restoring Support For Swap Files With Linux 4.21

[aht0]

Btrfs is considered reliable and is the default filesystem on openSuse.

For / yes. For /home it's xfs.

[starshipeleven]

The packaging mechanism is not stable in suse stuff. I tried to install tumbleweed and it failed to my custom package selection because dependencies problems that are solved in Debian 20 years ago.

That's plain bs, zypper or Yast's graphical package manager asks the user how to solve package conflicts and issues, and you can EASILY have it keep old dependencies or ignore new package dependencies (to the contrary of apt in Debian where if there are package conflicts or overwriting things you ALWAYS need to go and manually invoke dpkg with arcane rituals to force shit).

[starshipeleven]

Because it has taken 9 years to support file swap.

That's a feature that has nothing to do with stability of the file system.

Adding support for swap required specific work because btrfs works differently than other filesystems (namely it's CoW).

Afaik using swap files on ZFS (another CoW file system) is still not supported, and you have to use a swap "volume" in ZFS. Is ZFS unstable shit? No it's not.

[uid313]

That's a feature that has nothing to do with stability of the file system.

Adding support for swap required specific work because btrfs works differently than other filesystems (namely it's CoW).

Afaik using swap files on ZFS (another CoW file system) is still not supported, and you have to use a swap "volume" in ZFS. Is ZFS unstable shit? No it's not.

Ah, I see. Thanks for the explanation.
I just assumed swap on file was a basic functionality to expected on all file systems. Seeing as it taken 9 years, I started questioning the whole file system.

[aht0]

Afaik using swap files on ZFS (another CoW file system) is still not supported, and you have to use a swap "volume" in ZFS. Is ZFS unstable shit? No it's not.

Historic Unices AFAIK used generally swap devices. Using a file for it is Linux's kink. Correct me if I am in the wrong.
ZFS was originally built exclusively for SunOS, which was Unix.

[Charlie68]

For / yes. For /home it's xfs.

Soon the default setting of openSUSE and SUSE should change and by default / home should be a subvolume.
I remain of the opinion that if you do not care about the snapshots or other things of Btrfs you can easily stay with Ext4, there are no reasons to change, but if like me you need to have a system that can be restored in a few minutes in case of problems, then Btrfs is the right choice, because at the moment it is the only one that allows this. Then we can be fans of this or that, but this is reality.
The only thing that I would like to point out is that it has been using Btrfs for 2 years both for / and for the /home and I have never had any problem of data corruption or anything like that, so for me Btrfs is reliable.

[Vistaus]

9 years and its still not stable and reliable?
I guess I will be using ext4 forever.

Guess you aren't using Wine either, given how long it took them to get the 1.0 stable release out.

[uid313]

Guess you aren't using Wine either, given how long it took them to get the 1.0 stable release out.

I don't. I used to use Wine long time ago. But now everything runs natively on Linux or is on the web.

[starshipeleven]

Historic Unices AFAIK used generally swap devices. Using a file for it is Linux's kink. Correct me if I am in the wrong.
ZFS was originally built exclusively for SunOS, which was Unix.

I have extremely limited experience with old Unix stuff, but I'm pretty sure that its Oracle's Solaris (its kernel) supports swap files on UFS.

Swap files work by basically bypassing the filesystem logic and handing over raw access to the allocated space to the kernel. The swap writes aren't going through the filesystem at all, it's not like writing inside a file mounted as a loop device.
This is not particularly hard for a conventional filesystem that won't touch a file unless it's specifically asked to do so, that does not span multiple devices on its own, and that does not implement RAID at the filesystem level.

For both btrfs and zfs you have to put in place some additional logic to deal with that, as a CoW filesystem that can do RAID on its own could really do all sorts of stuff you don't want to do to swap space.

ZFS does it by segregating swap in its own zvol (which is somewhat like a partition in a LVM setup, so it's just as flexible as a swap file, but it's not a swap file), on btrfs they implemented logic to have the filesystem properly ignore these files when doing its own things, which is generic and can be used for whatever else too.

[starshipeleven]

Soon the default setting of openSUSE and SUSE should change and by default / home should be a subvolume.

Some clarification: this is what OpenSUSE does if you untick the "keep Home separate" and use a btrfs root on installation.

I've been running like that for 2 years now and it was set up and dealt with by the installer, it's not new stuff, they can change the default pretty easily.