From owner-freebsd-fs@FreeBSD.ORG Thu Nov 8 19:39:14 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 0C694DD3 for ; Thu, 8 Nov 2012 19:39:14 +0000 (UTC) (envelope-from ndenev@gmail.com) Received: from mail-ea0-f182.google.com (mail-ea0-f182.google.com [209.85.215.182]) by mx1.freebsd.org (Postfix) with ESMTP id 8CEE88FC1A for ; Thu, 8 Nov 2012 19:39:13 +0000 (UTC) Received: by mail-ea0-f182.google.com with SMTP id c10so1550330eaa.13 for ; Thu, 08 Nov 2012 11:39:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=subject:mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to:x-mailer; bh=IY3YJ0EuCZ1COFeWAn7hkhpP6vi5MFH08ihryHC1ItQ=; b=QPQcScL0lPOlMwmmUUXxPxrCtT8IWotat10YVk9MGBk1mwfmcVNGA0YR8Q6n6WBpjF o5BmtT5edB99sXIyUQVvGMp5GLNPc2aDSTWpWJCWX0WJMZRUIZNExzUdRB3/7kp8eBeX d1UaLllyAN3Q2xFMsokmkIwr00iCyzKf/rHkx1B0YWAA2LQCUB4mp2tLxYYthtecntbQ eoa51/42+FiceceV/jbKoJw4wALyCbI3pCd6FYWwWxSodPgu8pUL/K5RRgxSL1E3Oh5o FxFYfGlAmdUJxuqgrj7cxBMqu/VTcsnhRSIccc4Q+diaLY1LA1DaOZZo0DK/aJ3lCyWU +zDg== Received: by 10.14.223.4 with SMTP id u4mr30272181eep.19.1352403552742; Thu, 08 Nov 2012 11:39:12 -0800 (PST) Received: from [10.0.0.86] ([93.152.184.10]) by mx.google.com with ESMTPS id g5sm72066772eem.4.2012.11.08.11.39.10 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 08 Nov 2012 11:39:11 -0800 (PST) Subject: Re: zfs remove vdev functionality Mime-Version: 1.0 (Mac OS X Mail 6.2 \(1499\)) Content-Type: text/plain; charset=us-ascii From: Nikolay Denev In-Reply-To: <509BF0A2.2050600@digsys.bg> Date: Thu, 8 Nov 2012 21:39:09 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: <393C72B3-7231-47C6-ABD2-1C6BA166ED11@gmail.com> References: <509BF0A2.2050600@digsys.bg> To: Daniel Kalchev X-Mailer: Apple Mail (2.1499) Cc: freebsd-fs@freebsd.org X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Nov 2012 19:39:14 -0000 On Nov 8, 2012, at 7:49 PM, Daniel Kalchev wrote: > I was thinking on how to implement vdev removal on ZFS and came to = this idea: >=20 > If we can have an per-vdev flag that prohibits new allocations on the = vdev, but permits reads and frees - then we could mark so the vdev we = intend to remove form the zpool and issue an scrub-like command that = will rewrite all blocks allocated form that particular vdev. Since ZFS = is COW, this will effectively move all blocks off that "no write" vdev = and we can now detach it. >=20 > All this could be implemented with the new ZFS feature flags, so no = version bumps etc are necessary. >=20 > Is there something I didn't think of? >=20 > Daniel > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" I don't think this will be that easy, because of snapshots, clones etc. There was a project that you are probably aware of called BP Rewrite = (block pointer rewrite), that was interrupted by Sun-Oracle merger. It very well may be still = being worked on in Sun, who knows :) The closest thing to your idea that I seem to find is this : = https://www.illumos.org/issues/1051 Cheers, Nikolay=