From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from atl4mhob07.myregisteredsite.com ([209.17.115.45]:54668 "EHLO atl4mhob07.myregisteredsite.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753432Ab3E0QmG (ORCPT ); Mon, 27 May 2013 12:42:06 -0400 Received: from mailpod1.hostingplatform.com ([10.30.71.113]) by atl4mhob07.myregisteredsite.com (8.14.4/8.14.4) with ESMTP id r4RGg4IB025934 for ; Mon, 27 May 2013 12:42:04 -0400 Message-ID: <51A38CE5.1010003@chinilu.com> Date: Mon, 27 May 2013 09:42:13 -0700 From: George Mitchell Reply-To: george@chinilu.com MIME-Version: 1.0 To: =?UTF-8?B?U3rFkXRzIMOBa29z?= CC: linux-btrfs@vger.kernel.org Subject: Re: systemd "journalctl" is 1.89sec on ext4, 1.49 min on btrfs References: <16735484.PAleCPYpY8@noname> In-Reply-To: <16735484.PAleCPYpY8@noname> Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: I have gotten what appear to be large increases in speed out of btrfs by defragmentation of meta data. The manual defragmentation process takes forever as you have to defragment incrementally directory by directory. I was at the point where KDE startup times were getting abysmal (along with journalctl, etc) and the multiple drives would churn incessantly on startup. In the case of KDE, I found almost magical improvement with one operation: `btrfs filesystem defrag /usr/share`. I am currently going through the whole system deframenting directory by directory. Its amazing, it proceeds quite quickly and then hits a directory at random where it sits and plods away seemingly forever before moving on. I am convinced that there is something going on here with meta data fragmentation that, at times, is seriously affecting performance. I *think* that autodefrag, once its out the door will hopefully solve this, in the mean time I am trying to come up with some sort of way to schedule an anacron job to deal with this issue. But my suggestion would be that you try defragging your /var filesystem as thoroughly as possible on the meta data side. On 05/27/2013 09:21 AM, Szőts Ákos wrote: > Dear list, > > I have two openSUSE 12.3 systems with kernel 3.9. On one of them there's an > ext4 partition, while on the other there's a btrfs. > > I issued a "time journalctl -b --no-pager" command on both systems. This shows > the logs from the current boot without passing them to "less". > > On ext4 (3.9.3): > real 0m1.898s > user 0m0.291s > sys 0m0.105s > > On btrfs (3.9.2): > real 1m49.698s > user 0m0.102s > sys 0m0.470s > > Journalctl on btrfs was always this slow, some btrfsck were made on the file > system too, but I don't think it was corrupted. On just the first run it's > sluggish, after it's fast as the ext4 one. > > Is it a known issue or can I help somehow debugging this further? > > Best regards, > > Ákos Szőts > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > >