From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher James Halse Rogers Subject: Re: [bcachefs] time of mounting filesystem with high number of dirs Date: Fri, 09 Sep 2016 12:07:18 +1000 Message-ID: <1473386838.30693.4@mail.cooperteam.net> References: <5c0639691edb57d1b63b06effb5283d1@mejor.pl> <20160907211212.6pvxo7p5z3v2nvhf@kmo-pixel> <20160909015629.356sy3q4gg35szbn@kmo-pixel> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Return-path: Received: from mail.cooperteam.net ([150.101.105.211]:60322 "EHLO mail.cooperteam.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751685AbcIICHY (ORCPT ); Thu, 8 Sep 2016 22:07:24 -0400 Received: from [192.168.188.40] (unknown [192.168.1.1]) (using TLSv1 with cipher ECDHE-ECDSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: chris) by mail.cooperteam.net (Postfix) with ESMTPSA id 9B93A787063 for ; Fri, 9 Sep 2016 12:07:18 +1000 (AEST) In-Reply-To: <20160909015629.356sy3q4gg35szbn@kmo-pixel> Sender: linux-bcache-owner@vger.kernel.org List-Id: linux-bcache@vger.kernel.org To: linux-bcache@vger.kernel.org On Fri, Sep 9, 2016 at 11:56 AM, Kent Overstreet wrote: > On Wed, Sep 07, 2016 at 01:12:12PM -0800, Kent Overstreet wrote: >> So, right now we're checking i_nlinks on every mount - mainly the >> dirents >> implementation predates the transactional machinery we have now. >> That's almost >> definitely what's taking so long, but I'll send you a patch to >> confirm later. > > I just pushed a patch to add printks for the various stages of > recovery: use > mount -o verbose_recovery to enable. > > How many files does this filesystem have? (df -i will tell you). > > As another data point, on my laptop mounting takes half a second - > smallish > filesystem though, 47 gb of data and 711k inodes (and it's on an > SSD). My > expectation is that mount times with the current code will be good > enough as > long as you're using SSDs (or tiering, where tier 0 is SSD) - but I > could use > more data points. FWIW, I've got a tier 0 SSD in front of two 3TB HDDs, 1.8M inodes and 150GB used, and that takes 380ms to mount if systemd-analyse is to be trusted.