Tip of the Trade: ZFS on Leopard

By Carla Schroder (Send Email)
Posted Mar 17, 2008


ZFS, the space-age filesystem developed by Sun, is now available for Mac OS X Leopard. You can get the binaries and source code from ZFS on OS X. Be warned that this is a beta version — fun for testing and learning but not ready for mission-critical systems. Coming soon to a Mac near you -- the power of ZFS for Mac OS X Leopard is now in beta.

ZFS, all by itself, replaces the herd of separate filesystem management tools we've come to rely on: fsck, dump, restore, mkfs, tunefs, volume managers like EVM and LVM, raidtools, mdadm, rysnc, quota, fdisk, and all the rest. Mac OS X uses HFS+, which is a perfectly good journaling filesystem. However, it's not in the same class as ZFS. This is not meant as a criticism, as very few filesystems are.

You can't have your root filesystem using ZFS, but if you have a large enough hard disk you can test all of its features, including pools and simple RAID setups. Don't do anything to the partition containing your root filesystem, and remember that every partition ZFS touches will be overwritten.

diskutil list displays your existing partitions. Creating a ZFS-formatted storage pool with two disk partitions is done like this:

# zpool create newpool /device1 /device2
zpool list shows your new storage pool. You could stop there, create a mountpoint and mount it, start putting data on it, and see what happens. zpool destroy newpool gets rid of it. Want to create a mirror? Try this:
# zpool create newmirror mirror /device1 /device2
There is a whole lot more you can do, and there are issues specific to Mac OS X, which you can read about at ZFS on OS X. Two helpful articles about ZFS are ZFS: Should You? and ZFS Adds Exciting Twist to Mundane World .

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