From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kent Overstreet Subject: Re: bcachefs with cache device and backing device Date: Tue, 17 May 2016 20:01:03 -0800 Message-ID: <20160518040103.GA13870@moria.home.lan> References: <573532E2.1040201@gemtalksystems.com> <20160513043603.GA1407@kmo-pixel> <573BD789.9030406@gemtalksystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pa0-f48.google.com ([209.85.220.48]:32895 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750759AbcEREBH (ORCPT ); Wed, 18 May 2016 00:01:07 -0400 Received: by mail-pa0-f48.google.com with SMTP id xk12so13307202pac.0 for ; Tue, 17 May 2016 21:01:07 -0700 (PDT) Content-Disposition: inline In-Reply-To: <573BD789.9030406@gemtalksystems.com> Sender: linux-bcache-owner@vger.kernel.org List-Id: linux-bcache@vger.kernel.org To: Martin McClure , chris@cooperteam.net Cc: linux-bcache@vger.kernel.org On Tue, May 17, 2016 at 07:46:33PM -0700, Martin McClure wrote: > On 05/12/2016 09:36 PM, Kent Overstreet wrote: > > > > Yeah - tiering replaces cache/backing devices > > > > IIRC, > > > > bcache format --tier 0 -C --tier 1 -C > > > > (the -C is going to go away at some point) > > > > Had a chance to play with this some more, but still not getting it to > work... > > Formatting seems to work, and once I do this: > > echo /dev/sdd1 > /sys/fs/bcache/register > echo /dev/nvme0n1 > /sys/fs/bcache/register > echo 1 > /sys/fs/bcache//blockdev_volume_create > > a /dev/bcache0 has been created. However, if I try to mount it: > > mount -t bcache /dev/bcache0 /mnt > > it says: > > mount: No such file or directory > > with a return code of 32, which is documented as "mount failure". > > At this point I reach the limit of my current understanding, but would > like to understand more. The intended mount path for multi device filesystems is currently broken... Chris got it working (to my surprise) by - I belive - registering all the devices via /sys/fs/bcache/register, and then mounting just one of the block devices - Chris, is that correct? FYI though: tiering mode is _not_ as well tested currently, and Chris managed to hit a bug when he completely filled up tier 0 and it then wouldn't mount, because the btree updates journal replay was doing wouldn't fit on tier 0 - and I haven't merged the fix I sent him because it was kind of a hack. But I just got back from vacation so I should be able to start working through these issues...