The Eleventh Annual Southern California Linux Expo
February 22-24, 2013
Hilton Los Angeles International Airport

ZFS Administration


ZFS was initially released under the open source CDDL License. However, after Oracle's purchase of Sun Microsystems, ZFS went closed source. There have been various efforts to port ZFS to the Linux kernel. However, because the mainline kernel is licensed under the GPL, and the CDDL license is incompatible with the GPL, ZFS will not become part of the mainline kernel. As such, ZFS can only come through FUSE or through a kernel module. The Lawrence Livermore National Labratory secured a contract to port the latest source code from ZFS to a Linux kernel module. The project home is found at It uses the ZFS version 5 and ZPOOL version 28. Features include:

  • Copy-on-write transactions
  • Software RAID levels 0, 1 RAIDZ1, RAIDZ2, RAIDZ3 and 10
  • Logical volume management
  • Caching through the ZIL and L2ARC with SSDs
  • The capacity is a full 128-bits
  • Built-in error checking and correcting
  • Infinite and automatic "time sliding" snapshots
  • Compression
  • Deduplication
  • End-to-end checksums

However, there are some current limitations to the Linux kernel module for ZFS. First, it doesn't support encryption. Oracle released ZFS native encryption with ZPOOL version 30, which we do not have the source code to. Further, you cannot reduce a pool by removing drives from the pool, as you could with native Linux kernel software RAID. ZFS has been available to the public since 2005, and has had all these years to mature, work out bugs, and stablize. As such, it should be considered as the modern filesystem of choice over Btrfs. Btrfs currently does not support compression, deduplication, encryption, parity-based RAID levels and a number of other features, and the feature set that it does support, is marked as highly experimental. Thus, ZFS for Linux is a compelling filesystem for corporations looking to deploy storage solutions.

Saturday, February 23, 2013 - 16:30 to 17:30