From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from syrinx.knorrie.org ([82.94.188.77]:50594 "EHLO syrinx.knorrie.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751287AbdICSiC (ORCPT ); Sun, 3 Sep 2017 14:38:02 -0400 Subject: Re: How to disable/revoke 'compression'? To: Adam Borowski , Cloud Admin Cc: linux-btrfs@vger.kernel.org References: <1504459921.8809.3.camel@cloud.haefemeier.eu> <20170903180636.ayrubvma7awbki6i@angband.pl> From: Hans van Kranenburg Message-ID: Date: Sun, 3 Sep 2017 20:30:59 +0200 MIME-Version: 1.0 In-Reply-To: <20170903180636.ayrubvma7awbki6i@angband.pl> Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 09/03/2017 08:06 PM, Adam Borowski wrote: > On Sun, Sep 03, 2017 at 07:32:01PM +0200, Cloud Admin wrote: >> Hi, >> I used the mount option 'compression' on some mounted sub volumes. How >> can I revoke the compression? Means to delete the option and get all >> data uncompressed on this volume. >> Is it enough to remount the sub volume without this option? Or is it >> necessary to do some addional step (balancing?) to get all stored data >> uncompressed. > > If you set it via mount option, removing the option is enough to disable > compression for _new_ files. Other ways are chattr +c and btrfs-property, > but if you haven't heard about those you almost surely don't have such > attributes set. > > After remounting, you may uncompress existing files. Balancing won't do > this as it moves extents around without looking inside; defrag on the other > hand rewrites extents thus as a side effect it applies new [non]compression > settings. Thus: ｢btrfs fi defrag -r /path/to/filesystem｣. > >> Beside of it, is it possible to find out what the real and compressed size >> of a file, for example or the ratio? > > Currently not. > > I've once written a tool which does this, but 1. it's extremely slow, 2. > insane, 3. so insane a certain member of this list would kill me had I > distributed the tool. Thus, I'd need to rewrite it first... Heh, I wouldn't do that, since I need you to do my debian uploads. :D But it would certainly help to be a bit less stubborn only wanting to code in the language that matches your country code. :O Or maybe I can help a bit, since it sounds like a nice one for the coding examples in the lib. ;] Days are getting shorter again, so the amount of indoor coding activity will hopefully increase a bit again soon. -- Hans van Kranenburg