From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:55846 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751470AbeBBVpe (ORCPT ); Fri, 2 Feb 2018 16:45:34 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0F5299090D for ; Fri, 2 Feb 2018 21:45:34 +0000 (UTC) Received: from tgill.bos.csb (unknown [10.18.25.8]) by smtp.corp.redhat.com (Postfix) with ESMTP id D4F557D973 for ; Fri, 2 Feb 2018 21:45:33 +0000 (UTC) Reply-To: tgill@redhat.com From: Todd Gill Subject: XFS over device mapper dm-thin device Message-ID: <147a1764-1988-4efd-4f02-e942a1001b4e@redhat.com> Date: Fri, 2 Feb 2018 16:45:33 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: linux-xfs@vger.kernel.org Hi, I'd like to be able to take a snapshot of an XFS filesystem on top of dm-thin. The goal for the snapshot is: - fast to complete (couple seconds or better) - independent of origin (UUID updated?) - read/write To satisfy the independent goal, I'm updating the UUID on the snapshot. Currently "xfs_admin -U xxx" takes in the ballpark of 14 seconds on my test system. Is there a better approach to achieve the goals? Or can the UUID update be changed to be faster? I realize the filesystem can be mounted with "nouuid" option, but would prefer to avoid the possible trouble of duplicate UUIDs. This is a test script I've used to illustrate the time of "xfs_admin -U": https://pastebin.com/PFA5YRuH Thanks for any help, Todd