From: Jacek Luczak Subject: Re: getdents - ext4 vs btrfs performance Date: Thu, 1 Mar 2012 15:43:41 +0100 Message-ID: References: <20120229144244.GF5054@shiny> <20120301141823.GV5054@shiny> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE To: Chris Mason , Jacek Luczak , Hillf Danton , linux-ext4@vger.kernel.org, linux-fsdevel , LKML , linux-btrfs@vger.kernel.org, lczerner@redhat.com Return-path: In-Reply-To: <20120301141823.GV5054@shiny> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org 2012/3/1 Chris Mason : > On Thu, Mar 01, 2012 at 03:03:53PM +0100, Jacek Luczak wrote: >> 2012/3/1 Hillf Danton : >> > On Thu, Mar 1, 2012 at 9:35 PM, Jacek Luczak wrote: >> >> >> >> While I was about to grab acp I've noticed seekwatcher with made = my day :) >> >> >> >> seekwatcher run of tar cf to eliminate writes (all done on 3.2.7)= : >> >> 1) btrfs: http://dozzie.jarowit.net/~dozzie/luczajac/tar_btrfs.pn= g >> >> 2) ext4: http://dozzie.jarowit.net/~dozzie/luczajac/tar_ext4.png >> >> 3) both merged: http://dozzie.jarowit.net/~dozzie/luczajac/tar_bt= rfs_ext4.png > > Whoa, seekwatcher makes it pretty clear. Yep, ext4 is close to my wife's closet. >> >> >> >> I will send acp results soon. >> >> >> > Would you please take reiserfs into account? >> >> As of now not (lack of time) but I'm pretty close to consider XFS in >> the game. Whenever I will have more time and there won't be a pressu= re >> on giving host back to production I will redo same tests for reiserf= s. >> >> Now I'm focused on the userspace sorting results. > > reiserfs should have results very similar to ext4. =A0The directory > hashing used by reiserfs is going to result in a very random read > pattern. > > XFS will probably beat btrfs in this test. =A0Their directory indexes > reflect on disk layout very well. True, but not that fast on small files. Except the question I've raised in first mail there's a point in all those action. We are maintaining host that are used for building software: random access, lot of small files and dirs (always a co), heavy parallel IO. We were testing XFS vs ext4 a year ago and XFS was around 10% slower on build times. We did not - yet - done same on btrfs. Now we're looking for replacement for ext4 as we suffer from those issue - but we were not aware of that until stepped into this issue. If you would like me to do some specific tests around ext4 and btrfs, let me know. -Jacek