From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:51410 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755731AbaENNfC (ORCPT ); Wed, 14 May 2014 09:35:02 -0400 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1WkZKh-0007nI-UZ for linux-btrfs@vger.kernel.org; Wed, 14 May 2014 15:34:55 +0200 Received: from ip68-231-22-224.ph.ph.cox.net ([68.231.22.224]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 14 May 2014 15:34:55 +0200 Received: from 1i5t5.duncan by ip68-231-22-224.ph.ph.cox.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 14 May 2014 15:34:55 +0200 To: linux-btrfs@vger.kernel.org From: Duncan <1i5t5.duncan@cox.net> Subject: Re: [PATCH] mkfs.btrfs: allow UUID specification at mkfs time Date: Wed, 14 May 2014 13:34:40 +0000 (UTC) Message-ID: References: <5372C457.3000706@redhat.com> <53731BE3.5010604@cn.fujitsu.com> <537360B2.50107@swiftspirit.co.za> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Brendan Hide posted on Wed, 14 May 2014 14:25:22 +0200 as excerpted: > On 14/05/14 09:31, Wang Shilong wrote: >> On 05/14/2014 09:18 AM, Eric Sandeen wrote: >>> Allow the specification of the filesystem UUID at mkfs time. >>> >>> (Implemented only for mkfs.btrfs, not btrfs-convert). >> Just out of curiosity, this option is used for what kind of use case? >> I notice Ext4 also has this option.:-) > Personally I can't think of any "average" or "normal" use case. The > simplest case however is in using predictable/predetermined UUIDs. AFAIK the most common use-case would be when redoing filesystems already listed in fstab with UUID= mounting. I use and prefer LABEL= instead of UUID= mounting here, but I commonly keep a working and at least one identically sized partition backup filesystem copy of all non-throw-away filesystems, with fstab entries for both the working and backup versions, and periodically do a mkfs and recopy of the backup, with occasional boots to the backup and mkfs and recopy of the working version as well. As I use LABEL= fstab entries I ensure that I specify the same label at mkfs time so I don't have to redo the fstab, and people that use UUID= fstab entries would find the ability to specify UUID at mkfs time as useful as I do the ability to specify label. =:^) Many grub2 configurations also uses UUID so the same idea applies there. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman