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I just wish the ZFS could be more tightly integrated into Linux than it can (due to licensing). Would be nice to not have two implementations of a crypto syste

I just wish the ZFS could be more tightly integrated into Linux than it can (due to licensing). Would be nice to not have two implementations of a crypto system, a raid parity computation system, block caching, allocation, etc. Oh well...

loeg 8y ago
I hear you, especially on the block caching. ARC just does not interact well with FreeBSD's native block cache either.
- Teknoman117 8y ago
  The thing that really annoys me (if there is a way to fix this, please, comment) is that for zvols, whenever you read or write them, the blocks end up in both the ARC _and_ the Linux Page Cache.
johnny22 8y ago
is it just licensing? Doesn't it do its own thing in the vfs layer and perhaps others in a way that it wouldn't be accepted upstream either way?
- loeg 8y ago
  I don't see any reason ZoL couldn't stub out their own CDDL implementations and invoke Linux functions directly, where they are a suitable replacement. The problem is almost always going to be that ZFS was designed for Solaris and adapting it to use Linux APIs is non-trivial. The code duplication bothers me less than the page cache duplication / cache reclaim logic integration.
  - Teknoman117 8y ago
    It's not just to reduce the amount of ZoL specific work. If I understand correctly, the developers were saying there are specific parts of Linux where anything using them is considered a derivative work, and therefore even distributing source would be a violation of GPL. An instance of this is the crypto layer that was added in recently with the native dataset encryption. SPL actually reimplements this logic because the ZoL maintainers claim they can't use the Linux crypto subsystem without violating GPL.
- Teknoman117 8y ago
  It does do various things which the Linux kernel maintainers don't like (particularly how tightly integrated all the components are, something something "rampant layering violation"). While getting ZFS in-tree would be a godsend, I don't mind building as an out-of-tree module, just that it would be nice if didn't duplicate so much functionality.

loeg 8y ago

I hear you, especially on the block caching. ARC just does not interact well with FreeBSD's native block cache either.

Teknoman117 8y ago
The thing that really annoys me (if there is a way to fix this, please, comment) is that for zvols, whenever you read or write them, the blocks end up in both the ARC _and_ the Linux Page Cache.

johnny22 8y ago

is it just licensing? Doesn't it do its own thing in the vfs layer and perhaps others in a way that it wouldn't be accepted upstream either way?

loeg 8y ago
I don't see any reason ZoL couldn't stub out their own CDDL implementations and invoke Linux functions directly, where they are a suitable replacement. The problem is almost always going to be that ZFS was designed for Solaris and adapting it to use Linux APIs is non-trivial. The code duplication bothers me less than the page cache duplication / cache reclaim logic integration.
- Teknoman117 8y ago
  It's not just to reduce the amount of ZoL specific work. If I understand correctly, the developers were saying there are specific parts of Linux where anything using them is considered a derivative work, and therefore even distributing source would be a violation of GPL. An instance of this is the crypto layer that was added in recently with the native dataset encryption. SPL actually reimplements this logic because the ZoL maintainers claim they can't use the Linux crypto subsystem without violating GPL.
Teknoman117 8y ago
It does do various things which the Linux kernel maintainers don't like (particularly how tightly integrated all the components are, something something "rampant layering violation"). While getting ZFS in-tree would be a godsend, I don't mind building as an out-of-tree module, just that it would be nice if didn't duplicate so much functionality.