From owner-freebsd-fs@FreeBSD.ORG Wed Aug 8 15:41:45 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 700CF106566B for ; Wed, 8 Aug 2012 15:41:45 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-lb0-f182.google.com (mail-lb0-f182.google.com [209.85.217.182]) by mx1.freebsd.org (Postfix) with ESMTP id E8EAD8FC17 for ; Wed, 8 Aug 2012 15:41:44 +0000 (UTC) Received: by lbbgk8 with SMTP id gk8so676770lbb.13 for ; Wed, 08 Aug 2012 08:41:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=14Kf5avZ5vhWwHcIjcuZ3u6pcP4dx+Mrj6WEH2tghB0=; b=0O9zRdhqGmh5HsBgCdGiVEhKwcCq3/KP3GzzLOjSNCQtZU5bJhgh5XhdgRWet+FgWY vLC5fWFGSWnBC8xt5WPfwfYlxYo4Wsv+rQvztaR8k4fkVsy9QNk1Px4m9d+JdHGec0dc 0AQtbXsGmrUlaYt1hDmFLmnyhU+zuriYFLqAeCbDq/NNLaVZOKBc4Uu00YuolBLOKnBD 6Ma/C4tpXFFkYmeKqoby8XypiVXWgBjEic/6ac6Sqh0xJ591wdeU/0xJes3WaQU/PouC jhbZJw+dVNLVrTLqxsXNbRkTQ6XD4ksy13kDZqIXtVDNmFdmE7Zyxl1UixUxSYS1DcBd d+wQ== MIME-Version: 1.0 Received: by 10.152.105.173 with SMTP id gn13mr18587587lab.20.1344440503541; Wed, 08 Aug 2012 08:41:43 -0700 (PDT) Received: by 10.114.16.229 with HTTP; Wed, 8 Aug 2012 08:41:43 -0700 (PDT) In-Reply-To: <0c8801cd757a$601018e0$20304aa0$@simons-rock.edu> References: <0c8801cd757a$601018e0$20304aa0$@simons-rock.edu> Date: Wed, 8 Aug 2012 08:41:43 -0700 Message-ID: From: Freddie Cash To: Brian Gold Content-Type: text/plain; charset=UTF-8 Cc: freebsd-fs@freebsd.org Subject: Re: undoing zfs deduplication X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 08 Aug 2012 15:41:45 -0000 On Wed, Aug 8, 2012 at 8:27 AM, Brian Gold wrote: > I've got a system running 9.0-release w/ a zfs v28 pool. Within that pool I have 3 datasets, two of which have deduplication > enabled. I've recently been having a lot of performance issues with deduplication and have determined that I need far more ram that > I currently have in order to support dedupe. I don't have the budget for the ram necessary so I would like to move away from > deduplication. I'm aware that you can't simply turn dedupe off, you need to completely nuke the filesystem. > > What I'm wondering is, would it be possible for me to create new datasets within the same pool (I have a ton of available space) and > use a combination of "zfs send" & "zfs receive" to migrate my deduped datasets and all of their snapshots (daily, weekly, & monthly) > over to the new dataset? Yes, that is the only option for "un-deduping" a filesystem. zfs send/recv from the deduped filesystem to one with dedup=off. Then delete the deduped filesystem. Note: a "zfs destroy" will use a lot of RAM as it has to go through an update all the DDT entries. You may have to manually delete individual snapshots, and then manually delete individual directories in the filesystem, before destroying the actual filesystem. You may run into a situation where you don't have enough RAM/ARC to destroy a deduped filesystem. -- Freddie Cash fjwcash@gmail.com