From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mo4-p00-ob.smtp.rzone.de ([81.169.146.221]:23726 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751861AbdGXOMs (ORCPT ); Mon, 24 Jul 2017 10:12:48 -0400 Received: from mordor.fritz.box (xd932dc59.dyn.telefonica.de [217.50.220.89]) by smtp.strato.de (RZmta 41.1 DYNA|AUTH) with ESMTPSA id 40bde3t6OECkoSN (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (curve secp521r1 with 521 ECDH bits, eq. 15360 bits RSA)) (Client did not present a certificate) for ; Mon, 24 Jul 2017 16:12:46 +0200 (CEST) Message-ID: <1500905566.2781.8.camel@cloud.haefemeier.eu> Subject: Re: Best Practice: Add new device to RAID1 pool From: Cloud Admin To: linux-btrfs@vger.kernel.org Date: Mon, 24 Jul 2017 16:12:46 +0200 In-Reply-To: <18d96f74-00a8-9bb9-dddc-f50940d0971e@gmail.com> References: <1500895655.2781.6.camel@cloud.haefemeier.eu> <18d96f74-00a8-9bb9-dddc-f50940d0971e@gmail.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Am Montag, den 24.07.2017, 09:46 -0400 schrieb Austin S. Hemmelgarn: > On 2017-07-24 07:27, Cloud Admin wrote: > > Hi, > > I have a multi-device pool (three discs) as RAID1. Now I want to > > add a > > new disc to increase the pool. I followed the description on https: > > //bt > > rfs.wiki.kernel.org/index.php/Using_Btrfs_with_Multiple_Devices and > > used 'btrfs add '. After that I called a > > balance > > for rebalancing the RAID1 using 'btrfs balance start '. > > Is that anything or should I need to call a resize (for example) or > > anything else? Or do I need to specify filter/profile parameters > > for > > balancing? > > I am a little bit confused because the balance command is running > > since > > 12 hours and only 3GB of data are touched. This would mean the > > whole > > balance process (new disc has 8TB) would run a long, long time... > > and > > is using one cpu by 100%. > > Based on what you're saying, it sounds like you've either run into a  > bug, or have a huge number of snapshots on this filesystem.   It depends what you define as huge. The call of 'btrfs sub list ' returns a list of 255 subvolume. I think this is not too huge. The most of this subvolumes was created using docker itself. I cancel the balance (this will take awhile) and will try to delete such of these subvolumes/snapshots. What can I do more? > What you  > described is exactly what you should be doing when expanding an > array  > (add the device, then run a full balance).  The fact that it's > taking  > this long isn't normal, unless you have very slow storage devices.