From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mondschein.lichtvoll.de ([194.150.191.11]:40569 "EHLO mail.lichtvoll.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752466AbbLNI7L convert rfc822-to-8bit (ORCPT ); Mon, 14 Dec 2015 03:59:11 -0500 From: Martin Steigerwald To: Qu Wenruo Cc: Btrfs BTRFS Subject: Re: still kworker at 100% cpu in all of device size allocated with chunks situations with write load Date: Mon, 14 Dec 2015 09:59:09 +0100 Message-ID: <36270119.ZeTm4UPz2S@merkaba> In-Reply-To: <566E827A.2020604@cn.fujitsu.com> References: <8336788.myI8ELqtIK@merkaba> <5373860.W0QrVGf34G@merkaba> <566E827A.2020604@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi Qu. I reply to the journal fs things in a mail with a different subject. Am Montag, 14. Dezember 2015, 16:48:58 CET schrieb Qu Wenruo: > Martin Steigerwald wrote on 2015/12/14 09:18 +0100: > > Am Montag, 14. Dezember 2015, 10:08:16 CET schrieb Qu Wenruo: > >> Martin Steigerwald wrote on 2015/12/13 23:35 +0100: […] > >> GlobalReserve is just a reserved space *INSIDE* metadata for some corner > >> case. So its profile is always single. > >> > >> The real problem is, how we represent it in btrfs-progs. > >> > >> If it output like below, I think you won't complain about it more: > >> > merkaba:~> btrfs fi df / > >> > Data, RAID1: total=27.98GiB, used=24.07GiB > >> > System, RAID1: total=19.00MiB, used=16.00KiB > >> > Metadata, RAID1: total=2.00GiB, used=728.80MiB > >> > >> Or > >> > >> > merkaba:~> btrfs fi df / > >> > Data, RAID1: total=27.98GiB, used=24.07GiB > >> > System, RAID1: total=19.00MiB, used=16.00KiB > >> > Metadata, RAID1: total=2.00GiB, used=(536.80 + 192.00)MiB > >> > > >> > \ GlobalReserve: total=192.00MiB, used=0.00B > > > > Oh, the global reserve is *inside* the existing metadata chunks? Thats > > interesting. I didn´t know that. > > And I have already submit btrfs-progs patch to change the default output > of 'fi df'. > > Hopes to solve the problem. Nice. Thank you. It clarifies it quite a bit. I always wondered why its single. On which device does it allocate it in a RAID 1? Also can the data stored in there temporarily be recreated in case of loosing a device? In case that not, BTRFS would not guarantee that one device of a RAID 1 can fail at all times. Ciao, -- Martin