When Will ZFS Come To Linux?
Phoronix: When Will ZFS Come To Linux?
One of the technological advantages that Sun's Solaris (and OpenSolaris) operating systems have over Linux is their ZFS file-system. ZFS has a number of features not found on any of the current-generation Linux file-systems and its a technology many Linux users (especially those in data centers) have long desired. Unfortunately, as ZFS is licensed under Sun's CDDL (Common Development and Distribution License) instead of the GNU GPLv2 or GPLv3, this file-system hasn't been supported within the Linux kernel...
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Even if the license and patent issues were sorted out there are still big problems with bringing ZFS to Linux. The "rampant layering violations" not only make the whole FS unpalatable to some kernel developers, but also make the code more difficult to integrate into the Linux kernel. Big changes would have to be made to the VFS layer, and a new IO caching scheme would have to be incorporated.
The FUSE project looks pretty dead right now. It works, but no developers are really working on it. Somehow some big functionality and performance improvements were recently made but they're just sitting as patches and notes on the mailing list and haven't been committed to the main source code repository. Also, zfs-fuse requires things to be cached twice -- once by ZFS's ARC cache, and once by Linux's own caching mechanisms.