Deduplication and L2ARC in ZFS would be nice to have. Does OpenSolaris support them? I can't quite figure out which version of Solaris they are in, and how that maps to OpenSolaris. Are they there? If not, do you know when they are scheduled.


L2arc has been in OpenSolaris for a while now. Dedup is already in the development builds of OpenSolaris. If you can't wait until the next release here are some directions on how to upgrade to the development branch.

I run the development branch on my file server at home. Which is currently build 129. You have to be careful and wait a few days to make sure there aren't any gotcha's before doing an image-update but I haven't run into any problems doing this. And if you do you just reboot in the previous BE...gotta love zfs clones. I'm not using L2arc but I did play around with dedup a little the other day on a zfs volume.


It's coming either this month or next but only in dev builds for now, it may be in 128 but more likely a little after that. Sit tight, it'll be worth the wait :)

  • 2
    It's in svn_128a. The current dev build is svn_129. – user17642 Dec 14 '09 at 22:54

OpenSolaris' latest development releases support both dedup and L2ARC. Solaris 10 update 8 (which was released in October) has L2ARC, but not dedup.

The L2ARC code seems well tested and stable, and if you workload involves a lot of random reads, it is very likely to help.

The dedup code is not thoroughly baked at this time and I would recommend that you only use it on test machines without any important data.

To track the status: http://hub.opensolaris.org/bin/view/Community+Group+zfs/dedup and note in particular:

  • Pool might hang if large files or file systems are removed when dedup is enabled. See CR 6905936
  • System panic during operation after large amounts of data have been removed. See CR 6909931.

I am sure the bugs are being worked on, and dedup might be in a usable state sometime soon, but please don't jump into using a brand new feature in a development release until you are sure its level of stability matches your risk tolerance.


The easiest way to get dedup at present is to go to the GenUNIX site, download the latest OpenSolaris preview release on ISO, and install that. Choose one of the AI ISOs because the installer is better.


OpenSolaris ZFS deduplication was released in November. In development status for about a year.

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