From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:45060 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750768AbbI3P3t (ORCPT ); Wed, 30 Sep 2015 11:29:49 -0400 Date: Wed, 30 Sep 2015 17:28:47 +0200 From: David Sterba To: Hugo Mills , Austin S Hemmelgarn , =?iso-8859-1?Q?Gabr=EDel_Arth=FAr_P=E9tursson?= , linux-btrfs@vger.kernel.org Subject: Re: Add stripes filter Message-ID: <20150930152847.GK11442@suse.cz> Reply-To: dsterba@suse.cz References: <1443463025.16163.6.camel@system.is> <20150929120029.GX11442@twin.jikos.cz> <560A7FAB.1040607@gmail.com> <20150929122139.GF25907@carfax.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: <20150929122139.GF25907@carfax.org.uk> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Tue, Sep 29, 2015 at 12:21:39PM +0000, Hugo Mills wrote: > On Tue, Sep 29, 2015 at 08:10:19AM -0400, Austin S Hemmelgarn wrote: > > On 2015-09-29 08:00, David Sterba wrote: > > >On Mon, Sep 28, 2015 at 05:57:05PM +0000, Gabríel Arthúr Pétursson wrote: > > >>The attached patches to linux and btrfs-progs add support for filtering > > >>based on the number of strips in a block when balancing. > > > > > >What usecase do you want to address? As I understand it, this would help > > >the raid56 rebalancing to process only blockgroups that are not spread > > >accross enough devices. > > Exactly. Last week, I was trying to help Gabríel on IRC with a > close-to-full filesystem balance it to add some new devices in a > parity RAID configuration. He'd added the devices and balanced, but > the usage was unequal across the devices. The only way I could think > of dealing with it with the current tools was either to do a full > balance repeatedly until it worked itself out, or to delve into the > metadata with btrfs-debug-tree, and balance selected block groups > individually. > > I whinged that we needed a filter to pick just the block groups > that weren't "as full as possible", and Gabríel picked up the idea and > ran with it. That's great, thanks. The stripe filters are really missing.