Monthly Archives: September 2010

ZFS kernel module for Linux

UPDATE: If you are interested in ZFS on linux you have two options at this point:

I have been actively following the  zfsonlinux project because once stable and ready it should offer surperior performance due to the extra overhead that would be incurred by using fuse with the zfs-fuse project.

You can see another one of my posts concerning zfsonlinux here.


KQ Infotech has released (currently in closed beta) code that brings ZFS to Linux via a loadable kernel module.

Here is a link to the current and future feature set.  The reason that this is exciting is that although other ZFS implementations for Linux have traditionally existed, each of the available options have significant drawbacks.  For example  ZFS-FUSE is  implemented in userspace using FUSE, which has additional overhead due to the context switching that is required while switching back and forth between kernel-space and user -space. .

Another option is ZFS on Linux which provides a stable SPA, DMU and ZVOL layer, but does not however provide a Posix layer (ZPL) that would enable you to actually mount a ZFS filesystem from inside Linux.  From what I understand, KQ Infotech has basically taken some of the ZFS on Linux code that was developed by the Lawrence Livermore National Laboratory (LLNL), and actually implemented  the missing ZPL layer.

NPR was recently accepted into the closed beta program,  and I took some time last week to get this module installed on a Dell Poweredge 2950 running a 64 bit version of Ubuntu 10.04.  We are currently testing ZFS under  kernel version  2.6.32-24.  I have not had a ton of time to test things out, but I would say so far so good.  I plan on posting some ZFS and Btrfs benchmarks in the next few weeks after I get some time to better test performance, throughput, etc.

Btrfs: The Story So Far

Here is a link to a video presentation given by Josef Bacik, one of the 3 lead developers currently working on Btrfs.  This presentation was given at at LinuxCon Brazil 2010.  The video lasts about an hour and according to the description provides:

‘A look at the features that currently exist in Btrfs and what features are left to be done. We’ll look at stability and what things testers need to look out for. There will be plenty of benchmarks and use cases for the different features of Btrfs. We will also discuss what testing needs to be done, and how testers can help us developers.’

If you have some questions about the current state of Btrfs, current and future Btrfs development roadmap,  benchmarks, etc… you should take some time to watch this video.

Current state of “Btrfs” File System for Linux

Oracle has provided  a link to a webcast (registration required) on the state of Btrfs given,  by lead Btrfs developer Chris Mason.  Here is an excerpt from the webcast description:

‘Join Chris Mason, Director of Software Development at Oracle, the principal author of Btrfs flie system, and our own resident Linux kernel guru, as he discusses the development, features, benefits of the “Btrfs” file system (pronounced “Butter F S”, “B-tree F S”) in Linux.’

The video lasts about 1 hour and provides a very good overview of the current state of the file system, some of the pros and cons of Btrfs under various workloads, some of the features that have been implemented thus far, as well as some of the tools and features that a slated for future releases.