From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f68.google.com ([209.85.218.68]:36406 "EHLO mail-oi0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933331AbeFUVuN (ORCPT ); Thu, 21 Jun 2018 17:50:13 -0400 Received: by mail-oi0-f68.google.com with SMTP id 14-v6so4340762oie.3 for ; Thu, 21 Jun 2018 14:50:12 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <89d39e37-3944-f58d-018c-d36bdc9f870c@sandeen.net> References: <2a9a023d-fa37-59dc-caf2-c7c4167d3c75@levigo.de> <20180619161819.GD21698@magnolia> <20180621191535.GI7508@wotan.suse.de> <89d39e37-3944-f58d-018c-d36bdc9f870c@sandeen.net> From: Chris Murphy Date: Thu, 21 Jun 2018 15:50:11 -0600 Message-ID: Subject: Re: Mounting xfs filesystem takes long time Content-Type: text/plain; charset="UTF-8" Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Eric Sandeen Cc: "Luis R. Rodriguez" , "Darrick J. Wong" , "swadmin - levigo.de" , xfs list On Thu, Jun 21, 2018 at 1:19 PM, Eric Sandeen wrote: > > > On 6/21/18 2:15 PM, Luis R. Rodriguez wrote: >> On Tue, Jun 19, 2018 at 02:21:15PM -0500, Eric Sandeen wrote: >>> On 6/19/18 11:18 AM, Darrick J. Wong wrote: >>>> On Tue, Jun 19, 2018 at 02:27:29PM +0200, swadmin - levigo.de wrote: >>>>> Hi @all >>>>> I have a problem with mounting a large XFS filesystem which takes about >>>>> 8-10 minutes. >>>>> >>>>> >>>>> >>>>> :~# df -h /graylog_data >>>>> Filesystem Size Used Avail Use% Mounted on >>>>> /dev/mapper/vgdata-graylog_data 11T 5.0T 5.1T 50% /graylog_data >>>>> >>>>> ---- >>>>> >>>>> :~# xfs_info /dev/mapper/vgdata-graylog_data >>>>> meta-data=/dev/mapper/vgdata-graylog_data isize=512 agcount=40805, >>>>> agsize=65792 blks >>>> >>>> 41,000 AGs is a lot of metadata to load. Did someone growfs a 1G fs >>>> into a 11T fs? >>> >>> >>> >>> Let me state that a little more clearly: this is a badly mis-administered >>> filesystem; 40805 x 256MB AGs is nearly unusable, as you've seen. >>> >>> If at all possible I would start over with a rationally-created filesystem >>> and migrate the data. >> >> Considering *a lot* of folks may typically follow the above "trap", wouldn't it >> be wise for userspace to complain or warn when the user may want to do >> something stupid like this? Otherwise I cannot see how we could possibly >> conceive that this is badly administered filesystem. > > Fair point, though I'm not sure where such a warning would go. growfs? > I'm not a big fan of the "you asked for something unusual, continue [y/N]?" > type prompts. > > To people who know how xfs is laid out it's "obvious" but it's not fair to > assume every admin knows this, you're right. So calling it mis-administered > was a bit harsh. > The extreme case is interesting to me, but even more interesting are the intermediate cases. Is it straightforward to establish a hard and fast threshold? i.e. do not growfs more than 1000% from original size? Do not growfs more than X times? Or is it a linear relationship between performance loss and each additional growfs? -- Chris Murphy