Stephen Foskett, Pack Rat

ZFS: Super File System!

Posted on Feb 27, 2008 by Stephen

ZFS really piques my interest, so I just had to include it in my TechTarget storage virtualization seminar series.

Here’s a quick primer for those of you who aren’t familiar with it, and thus are wondering why anyone would get stoked over a filesystem!

ZFS (originally “zettabyte file system” but now just ZFS) takes the essential technolgy from file systems and volume managers and stirs it together into one important new way to manage storage.  It’s an open source project started and managed by Sun, using the CDDL license (so Richard Stallman wouldn’t approve).  It’s loved by both Sun and Apple which makes it much more important.

See, ZFS will probably replace UFS (on Sun), HFS+ (on Mac), and every other file system and volume management product out there, especially on these platforms.  And I expect to see it appear on Linux once the tricky bits are resolved (which have to do with licensing not technology…)

ZFS creates a truly flexible, extensible, and full-featured pool of storage across systems and disks.  No more (of the old) arcane syntax, commands, ridiculous GUIs (ahem, Sun), and unnatural limitations of old system storage management.  With ZFS, you add some disks, get some space, and use it.  But it gets cooler than that…

ZFS “zpools” (file systems) live on “vdevs” with striping and optional RAID-Z/Z2 (which is double-parity kinda like RAID-6).  And, get this, every block is protected with checksums to ensure that the rapidly rising incidence of disk errors won’t bite you.  Want capacity?  128-bit addresses mean near-infinite space (in theory).  Oh, yeah, and all blocks are “copy-on-write” for snapshots and clones, something that barely works on most desktops and workstations.

But alas, there are some limitations…  Adding (and especially removing) vdevs is hard (read: maybe impossible) depending on how your storage was set up.  Stacked RAID is impossible, so no “Z+Z2″ for you!  And, until Sun integrates Lustre, there is no clustering support.

And then there’s the fact that Sun and Network Appliance are actively suinging each other over the fact that the technology in ZFS has ended up looking an awful lot like their bread and butter super file system, WAFL.

So there you have it.  If you’ll be in Washington DC on March 4, or Durham NC on March 6 and are interested in this topic, and the wider world of storage and server virtualization, I’d love for you to register and attend this free seminar!

Tags: Apple, seminar, Storage Decisions, storage virtualization, Sun, TechTarget, ZFS