From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mondschein.lichtvoll.de ([194.150.191.11]:46601 "EHLO mail.lichtvoll.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751618AbeA1NHS (ORCPT ); Sun, 28 Jan 2018 08:07:18 -0500 From: Martin Steigerwald Subject: Re: [RFD] XFS: Subvolumes and snapshots.... Date: Sun, 28 Jan 2018 13:59:56 +0100 Message-ID: <10612480.yRmMisqFVa@merkaba> In-Reply-To: <20180125055144.qztiqeakw4u3pvqf@destitution> References: <20180125055144.qztiqeakw4u3pvqf@destitution> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="UTF-8" Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Dave Chinner Cc: linux-xfs@vger.kernel.org Dave Chinner - 25.01.18, 06:51: > The video from my talk at LCA 2018 yesterday about the XFS subvolume and > snapshot support I'm working on has been uploaded and can be found > here: > > https://www.youtube.com/watch?v=wG8FUvSGROw I somehow knew that something about snapshots would be coming for XFS after seeing the reflink / COW and online scrub/repair work by Darrick. But I am highly surprised on the how. I also did not really expect pNFS file layout of Christoph to play a role here. It totally makes sense to me right now, but on the other hand I found myself thinking "It can´t be that easy, can it?" after watching your talk. Easy not in amount of coding work needed and some complexities you mentioned, so I totally get that it is a lot of work needed to pull this off, but easy in terms of the concept behind it. Yet, if a concept is easy that is quite a hint that it might actually be a good one. And if you really can get away with it… then by all means, have a go at it! I am looking forward to this new "extraordinary way to eat your data" (Darrick) or create "blammo" and "kaboom" (Dave). :) >>From what I understand it is also way less of a "layering violation" than the approach in taken in BTRFS or ZFS. Actually it might not be a "layering violation" at all, since the different layers are still there and communicating with each other. Which opens a lot of potential on applying this to other filesystems and storage subsystems of the kernel. I see benefit in having more than one concept and learn from each other. Maybe even a new dog like BTRFS can learn a trick from an old dog at some point in time. It sounds crazy to me to think like this at the moment… but for a long time it sounded crazy to try to implement snapshots or subvolumes to traditional filesystems. Kudos to thinking out of the box! -- Martin