The (unstable and development-oriented only) filesystem Btrfs version 0.14 has been released. "Btrfs is a new copy on write filesystem for Linux aimed at implementing advanced features while focusing on fault tolerance, repair and easy administration. Initially developed by Oracle, Btrfs is licensed under the GPL and open for contribution from anyone."
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Member since:2005-11-15
Member since:2005-07-24
No. That is a mischaracterization. Btrfs is intended to work closely *with* dm and lvm. A certain minimum amount of functionality is duplicated between btrfs and the current dm and lvm where absolutely necessary. Read what Chris says about this:
http://lwn.net/Articles/265533/
Edited 2008-04-30 17:59 UTC
Member since:2005-07-08
So? What makes ZFS completely unsuitable for Linux is the fact that it's not just a filesystem - not even a "filesystem + volume manager". ZFS is a complete software stack from the VFS to the storage driver.
This is why ZFS supports io priorities and UFS-solaris doesn't: They have the "old" IO stack and the "new" ZFS stack. In the Linux kernel this would not be acceptable at all. When Linux develops a new piece of the IO stack such the io priorities, it must work for all the filesystems. If that piece only works with a filesystem, it'd be considered misdesigned and would not be merged. This is why in Linux you have IO priorities support not only for a given filesystem like ext3, but also for filesystems like FAT - for any kind of filesystems, in fact the io priority thing doesn't interacts so much with the filesystems, but with the block devices.
So if ZFS were GPL, some parts would be need to be redesigned to be merged in Linux. BTRFS, in the other hand, is just a filesystem that plugs cleanly in the Linux design.
Member since:
2005-07-24
An impedance mismatch between the ZFS architecture and Linux kernel architecture is *not* political, however. Sun's goals for ZFS, apparently, are for it the be the Solaris filesystem. And there is absolutely nothing wrong with that. That strategy has its strengths. And in that case, putting the layering of logical levels into ZFS itself makes perfect sense. However, supporting a broad range of filesystems is a strategy which also has its strengths, and that is what Linux does. In that case, having all the layering of raid, volume manager, fs, etc. in ZFS itself makes no sense at all.
No NIH is required to see that ZFS, while a good fit for Solaris, is a poor fit for Linux.
As to licensing... that does have a political aspect. But the problem is primarily a practical one from the Linux kernel devs standpoint. Although an argument could be made that Sun's choice of license might have been motivated by political (or perhaps "strategic" would be a better word) factors.
Edited 2008-04-30 16:44 UTC