From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from len.romanrm.net ([176.31.121.172]:36574 "EHLO len.romanrm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751879Ab3BZF5I (ORCPT ); Tue, 26 Feb 2013 00:57:08 -0500 Date: Tue, 26 Feb 2013 11:57:04 +0600 From: Roman Mamedov To: Suman C Cc: "Fajar A. Nugraha" , Mike Fleetwood , linux-btrfs Subject: Re: lvm volume like support Message-ID: <20130226115704.50102196@natsu> In-Reply-To: References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_//ZdqgVkZMQSZ2C73LqS/9KV"; protocol="application/pgp-signature" Sender: linux-btrfs-owner@vger.kernel.org List-ID: --Sig_//ZdqgVkZMQSZ2C73LqS/9KV Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Mon, 25 Feb 2013 21:35:08 -0800 Suman C wrote: > Yes, zvol like feature where a btrfs subvolume like construct can be > made available as a LUN/block device. This device can then be used by > any application that wants a raw block device. iscsi is another > obvious usecase. Having thin provisioning support would make it pretty > awesome. I think what you are missing is that btrfs is a filesystem, not a block dev= ice management mechanism. For your use case can simply create a snapshot and then make a sparse file inside of it. btrfs sub create foobar dd if=3D/dev/zero of=3Dfoobar/100GB.img bs=3D1 count=3D1 seek=3D100G If you need this to be a block device, use 'losetup' to make foobar/100GB.i= mg appear as one (/dev/loopX). But iSCSI/AoE/NBD can export files as well as b= lock devices, so this is not even necessary. --=20 With respect, Roman --Sig_//ZdqgVkZMQSZ2C73LqS/9KV Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAlEsTrAACgkQTLKSvz+PZwgcVgCeLBTFqv/s8vCp+TNX+I+v4Mab woMAnAzM+Dy9mwckAHhoU6cq7q6ol09b =dSUK -----END PGP SIGNATURE----- --Sig_//ZdqgVkZMQSZ2C73LqS/9KV--