From: Karel Zak Subject: Re: [PATCH 2/3] mke2fs: print extra information about existing ext2/3/4 file systems Date: Tue, 6 May 2014 09:44:55 +0200 Message-ID: <20140506074455.GB29151@x2.net.home> References: <1399295044-24489-1-git-send-email-tytso@mit.edu> <1399295044-24489-2-git-send-email-tytso@mit.edu> <20140505140401.GD22287@thunk.org> <20140505142808.GF22287@thunk.org> <20140505144423.GG22287@thunk.org> <20140505175049.GA29151@x2.net.home> <20140505183253.GL22287@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: =?utf-8?B?THVrw6HFoQ==?= Czerner , Ext4 Developers List , linux-fsdevel@vger.kernel.org To: "Theodore Ts'o" Return-path: Content-Disposition: inline In-Reply-To: <20140505183253.GL22287@thunk.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Mon, May 05, 2014 at 02:32:53PM -0400, Theodore Ts'o wrote: > > BTW, the current trend is to use GPT partition types to identify > > purpose of the partition filesystem (for example extra GUID for > > /home). It's FS independent solution and it allows use the right > > filesystems for the right mountpoints. It's very attractive for > > example for virtual images where you don't have to setup fstab and > > identify FS, but you still have (for example) /home on the right > > place. > > But a partition only gets one GUUID and one partition type. So are > you saying that the GUUID partition type would be used to indicate the > concept of "this is the file system for /home", *instead* of "this is > an btrfs file system" or "this is an ext4 file system"? Yes, GPT partition has two UUIDs, - UUID = an unique partition identifier - GUID = partition type identifier I talked about the type (GUID). Note that this concept is just another point of view how to mount partitions, I don't think it will be a mainstream solution for standard machines. Now it's supported by systemd. More details: http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/ For old good fstab you can use PARTUUID= to identify partitions and to bypass filesystem specific identifiers. In this case it's unique partition identifier, no partition type. Karel -- Karel Zak http://karelzak.blogspot.com