4 ms·

A CoW filesystem itself is not much more complicated than a plain filesystem. Or maybe a CoW softraid, with the filesystem existing at a different layer. ZFS h

A CoW filesystem itself is not much more complicated than a plain filesystem. Or maybe a CoW softraid, with the filesystem existing at a different layer. ZFS has countless bonus tunables, several types of caching distinct from the kernel VFS cache, its own write logs and special devices, multiple levels of topology (datasets in a pool consisting of vdevs consisting of drives), deduplication, compression, etc. It is also not at all user friendly. When set up right (and no changing your mind on setup), and when fed enough resources, it does it's job well, but simple or elegant cannot describe it.

klysm 4y ago
I completely agree with that assessment. The core ideas behind how the CoW work are elegant, but the implementation is anything but elegant.
masklinn 4y ago
You didn't answer the question. You can't claim that there are simpler solutions then not actually provide a simpler solution. Which handwaving is not. > A CoW filesystem itself is not much more complicated than a plain filesystem. And yet there isn't one out there, there's pretty much only ZFS and BTRFS, the latter having been in a state of almost-but-not-actually-working for over a decade now. bcachefs is the only contender and it remains a single-developer effort with little mainlining progress in the last few years.
- laumars 4y ago
  There’s also hammerfs. I’ve not used that though. I think the complaints levelled against ZFS is a little unfair though. I agree that there are more elegant ways to implement ZFS but actually what we have already works really damn well. And the comments about the CLI being hard to use is weird because having used a hell of a lot of different file systems over the years (including BtrFS), I’ve found ZFS to be remarkably easy. ZFS has saved me from a number of hardware failures. If it really were as bad as the comments on here have made out, it’s have lost data several times over.
- arghwhat 4y ago
  > You didn't answer the question. You can't claim that there are simpler solutions then not actually provide a simpler solution. And what was would be a reasonable response to you? Pasting a novel filesystem implementation as proof that the existing ones are overcomplicated? Opinions do not have a burden of evidence. There is a handful of CoW filesystems out there, showing that it is certainly not an insurmountable issue to write one. Rather, the problem is stopping people from doing more at this point, keeping the design simple instead. That we don't have something better yet is likely a result of writing filesystems in general being rather laborous to do right regardless of CoW, and being incredibly unrewarding - few care about filesystems unless it's broken.

klysm 4y ago

I completely agree with that assessment. The core ideas behind how the CoW work are elegant, but the implementation is anything but elegant.

masklinn 4y ago

You didn't answer the question. You can't claim that there are simpler solutions then not actually provide a simpler solution. Which handwaving is not. > A CoW filesystem itself is not much more complicated than a plain filesystem. And yet there isn't one out there, there's pretty much only ZFS and BTRFS, the latter having been in a state of almost-but-not-actually-working for over a decade now. bcachefs is the only contender and it remains a single-developer effort with little mainlining progress in the last few years.

laumars 4y ago
There’s also hammerfs. I’ve not used that though. I think the complaints levelled against ZFS is a little unfair though. I agree that there are more elegant ways to implement ZFS but actually what we have already works really damn well. And the comments about the CLI being hard to use is weird because having used a hell of a lot of different file systems over the years (including BtrFS), I’ve found ZFS to be remarkably easy. ZFS has saved me from a number of hardware failures. If it really were as bad as the comments on here have made out, it’s have lost data several times over.
arghwhat 4y ago
> You didn't answer the question. You can't claim that there are simpler solutions then not actually provide a simpler solution. And what was would be a reasonable response to you? Pasting a novel filesystem implementation as proof that the existing ones are overcomplicated? Opinions do not have a burden of evidence. There is a handful of CoW filesystems out there, showing that it is certainly not an insurmountable issue to write one. Rather, the problem is stopping people from doing more at this point, keeping the design simple instead. That we don't have something better yet is likely a result of writing filesystems in general being rather laborous to do right regardless of CoW, and being incredibly unrewarding - few care about filesystems unless it's broken.