Ubuntu's Zsys For OpenZFS Linux Installs Sees First Update In A Year

[Developer12]

I've been wondering - are filesystems *this* difficult to create? Because I also remember Microsoft starting ReFS introduced in 2012 which to this day is pretty much dead except servers maybe.

There are a few things that make filesystems difficult to get right, especially those that offer advanced features like copy-on-write or journaling etc.

If you want to make something like FAT then it's much more straightforward. Low performance, few features, and no assurance of integrity after a crash or power outage.

Implementing features like journaling and CoW without shooting yourself in the foot means dealing with really complicated order-of-operations. Made worse by unknown progress in the case of a crash or power outage. Add to that the fact that the easiest solutions (eg. global lock on the filesystem tree) are really bad for performance. Then of course this is with multiple simultaneously accessing programs, all trying to read and write files at the same time.

The fact that filesystems are persistent is also raises the stakes, as a problem with the fileystem will silently corrupt data in the background and can't be simply wiped out with a reboot. This alone is enough to keep filesystem developers (and users) worried.

EDIT:

Oh, and of course NONE of that even mentions trying to do integrity checking and *correction* on data. Correcting data errors means storing redundant copies or enough parity data, and routines for checking/fixing.

And then of course a problem could happen anywhere, including the structures outside the data that describe the filesystem and it's structure. You can't blindly trust *those* and have to be able to detect corruption there too, and recover from it.

[ResponseWriter]

Such a shame. I had high hopes for ZSys. Which other distribution offer you the option to make a system snapshot every time you do an update and the possibility to revert to a previous snapshot from Grub in case something breaks and have all of it working out of the box?

I've been using Timeshift with timeshift-autosnap-manjaro package on Manjaro for a while now but these are available for anything Arch based. OK, it took a manual step to install but it does pretty much as you've described.

[cl333r]

There are a few things that make filesystems difficult to get right (...)

I'd imagine they have automated testing that simulates errors and whatever and catches them. In the heavy industry they first create a digital version e.g. of a plane, test it virtually, and if it proves OK they proceed to implementing IRL and then test that. Thus I'd expect almost all filesystem errors to be caught before it's deployed to disks and tested there.

[Charlie68]

No one is forced to use BTRFS for data, I have personally been doing it for years and have never had any problems, despite various power outages.
However BTRFS is still the most sensible choice for a desktop pc / system.
Ubuntu is still there after years, with ridiculous support for desktop users. Every day I see users on the Ubuntu forums asking how to cancel an update, while the human distribution still fails to give a solution by default. Little human!

[Snaipersky]

Let's agree to disagree here. Valve' Steamdeck has a dual BTRFS/Ext4 setup because BTRFS doesn't handle their use-case just fine. ZFS, oddly enough, would have.

ZFS supports case folding? I seem to recall that was a big one for helping proton.

[Developer12]

I'd imagine they have automated testing that simulates errors and whatever and catches them. In the heavy industry they first create a digital version e.g. of a plane, test it virtually, and if it proves OK they proceed to implementing IRL and then test that. Thus I'd expect almost all errors to be caught before it's deployed to disks and tested there.

It's been a little while since I checked, but the ZFS test suite used to automatically generate datasets (filesystems) in all the different configurations, snapshot them, delete snapshots, add devices, remove devices, and all sort of other things, including simulating multiple system crashes during high IO, scrubs, and similarly important events. Really just absolutely hammer the thing.

[mdedetrich]

Let's agree to disagree here. Valve' Steamdeck has a dual BTRFS/Ext4 setup because BTRFS doesn't handle their use-case just fine. ZFS, oddly enough, would have.

What was the use case?

[skeevy420]

ZFS supports case folding? I seem to recall that was a big one for helping proton.

Yeppers.

zfs create -o casesensitivity=(mixed,sensitive,insensitive) pool/dataset

[skeevy420]

What was the use case?

Case sensitivity and modding. Extracting Windows game mods on Linux and casing them is one of the 9 levels of hell.

[RahulSundaram]

Case insensitivity...If BTRFS had case insensitivity they'd probably be using it for $HOME, too

Since Valve hasn't commented on this afaik, I would hesitate to assume this. COW based filesystems do have some advanced features but they come at a performance and resource usage cost and Steam deck can suffer from either of those. If this is truly desirable for Value, it doesn't look like it would be a big lift to support this.