From owner-freebsd-questions@freebsd.org Sun Jun 12 22:50:36 2016 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id BB046AF010D for ; Sun, 12 Jun 2016 22:50:36 +0000 (UTC) (envelope-from matthew@FreeBSD.org) Received: from smtp.infracaninophile.co.uk (smtp.infracaninophile.co.uk [IPv6:2001:8b0:151:1:c4ea:bd49:619b:6cb3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "smtp.infracaninophile.co.uk", Issuer "infracaninophile.co.uk" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4ADAE2ECB for ; Sun, 12 Jun 2016 22:50:36 +0000 (UTC) (envelope-from matthew@FreeBSD.org) Received: from liminal.local (CPE00180a85ab9a-CMbc4dfb2fc1a0.cpe.net.cable.rogers.com [174.112.18.129]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: m.seaman@infracaninophile.co.uk) by smtp.infracaninophile.co.uk (Postfix) with ESMTPSA id E486040BB for ; Sun, 12 Jun 2016 22:50:31 +0000 (UTC) Authentication-Results: smtp.infracaninophile.co.uk; dmarc=none header.from=FreeBSD.org Authentication-Results: smtp.infracaninophile.co.uk/E486040BB; dkim=none; dkim-atps=neutral Subject: Re: ZFS: Is 'zpool add' really irreversible? To: freebsd-questions@freebsd.org References: <86shwiax38.fsf@WorkBox.Home> <22e9b8aa-3171-f399-f3a8-b71eb92210f5@rawbw.com> From: Matthew Seaman Message-ID: <5022693a-b2e9-70d4-352b-121a116a0e20@FreeBSD.org> Date: Sun, 12 Jun 2016 18:50:25 -0400 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <22e9b8aa-3171-f399-f3a8-b71eb92210f5@rawbw.com> Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="xltGncTbbcbUDH6eXBomWTXanUvTV2u6g" X-Virus-Scanned: clamav-milter 0.99.2 at smtp.infracaninophile.co.uk X-Virus-Status: Clean X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00,RDNS_DYNAMIC, SPF_SOFTFAIL autolearn=no autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on smtp.infracaninophile.co.uk X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 12 Jun 2016 22:50:36 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --xltGncTbbcbUDH6eXBomWTXanUvTV2u6g Content-Type: multipart/mixed; boundary="Xo2max1P0fP3ReMaEeAQc5H5rrm62jthQ" From: Matthew Seaman To: freebsd-questions@freebsd.org Message-ID: <5022693a-b2e9-70d4-352b-121a116a0e20@FreeBSD.org> Subject: Re: ZFS: Is 'zpool add' really irreversible? References: <86shwiax38.fsf@WorkBox.Home> <22e9b8aa-3171-f399-f3a8-b71eb92210f5@rawbw.com> In-Reply-To: <22e9b8aa-3171-f399-f3a8-b71eb92210f5@rawbw.com> --Xo2max1P0fP3ReMaEeAQc5H5rrm62jthQ Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 12/06/2016 18:14, Yuri wrote: > On 06/12/2016 14:58, Brandon J. Wandersee wrote: >> `zpool add` adds*virtual* devices to a*pool*, while `zfs attach` adds= >> physical devices to a mirrored device. So individual disks can be adde= d >> to and removed from mirrored virtual devices, but virtual devices cann= ot >> be removed from a pool. >=20 >=20 > Thank you for your answer. I see that ZFS is designed this way. >=20 > But I can't say I like this part of ZFS design. Because this isn't a > physical disk with the set size, but a combination of disks. People may= > reasonably want to remove some disks in some layouts, due to failures, > etc, and ZFS just lacks the flexibility to do that. You should have seen Matt Ahren's talk at BSDCan this year. (It might be available on YouTube in the next few days -- depends if it was livestreamed or not. Unfortunately, while there were lecture 4 tracks, there was only one set of video kit to livestream with...) Suffice it to say though that there is already fix for those 'Oh No! I really didn't mean to type "zfs add" there' moments in the upstream OpenZFS repo, which will be coming to a FreeBSD repository near you Real Soon Now. You get a grace period within which you can undo that sort of mistake. Cheers, Matthew --Xo2max1P0fP3ReMaEeAQc5H5rrm62jthQ-- --xltGncTbbcbUDH6eXBomWTXanUvTV2u6g Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQJ8BAEBCgBmBQJXXec3XxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXQ2NTNBNjhCOTEzQTRFNkNGM0UxRTEzMjZC QjIzQUY1MThFMUE0MDEzAAoJELsjr1GOGkAT/JsQAJG3iotDrvsxmPuXTEw1VBy+ xs+l7Ut8pyRKtRCU1kh5NpKbtYy7rKNqFfMEqQBtbgOjPrh8hHGCznB+uvTtFrSw PE6Put2whxrKEcPzApRFL1UzE9U+lJKYgH263cC/SiR8Nqbv3JYbnGHSi1kz/S4+ cYSDahhe4o5nRIJioJ5NRYvd2BClfktOswdiVEhEdMXcJ3ODkEVTNMamwNofEbAY L2yG3I4e6PlNfQ7BPxZqZ8JYh98uLHdkrgl2aYwBgvgmjknX6jeswL8rbp5WxhNI IVukhdPe8x8cIFZVymVI9LeVqkHENJ8JKIdUihPU6VjWt50HSobeuMAtcTaR3ZrY JsoquNDDXBIvaLM9P1XLfyYu5FwqqDCiN/6iMCKETQZEafd3q2Boxuwq+fpBBa3I 1gY32fsg6C0iGH/H54vA1+lDxqq1bTFQPHQ+mv49/aHkNFWlLUs9DlLrpe7A6ok1 Y1pv07Xj/378tCEengzdyxhMoODHvAqS41JTxcNF61PwVIHKRj+eldt8T1GAK1IB KOeT+D6c0riFb8Rs8hFGcbic+9yqG6Mdq8qUvpS3NfE0lcyTqZ6jxutxE0UkNAfN 2tYeBtxz1PieG4pwM/dBIJNkZAql7X4Ym6SZoHh90dy6ldyqsj6rJQABUdePnuHZ eGDIipVguuJ1zfSK8naw =FUG7 -----END PGP SIGNATURE----- --xltGncTbbcbUDH6eXBomWTXanUvTV2u6g--