From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936242AbZDCSG0 (ORCPT ); Fri, 3 Apr 2009 14:06:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S935498AbZDCSFq (ORCPT ); Fri, 3 Apr 2009 14:05:46 -0400 Received: from mail-qy0-f118.google.com ([209.85.221.118]:38463 "EHLO mail-qy0-f118.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936179AbZDCSFn convert rfc822-to-8bit (ORCPT ); Fri, 3 Apr 2009 14:05:43 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; b=U174x5zeyLcS2bH1P0kHhtBkM18CvdskYl/YR9aeh5lat42AZDb0zx/QaRWGrqp9od 3MW9i5a2iiyV6TreBk1u4Z/0pvtObjdkOKqENMs3MueMYJB72qo78HMO76oEfrERy6tz U52R3gu7R+ZFzxY3s+/ThkAnPuZCDYsHc1cO8= MIME-Version: 1.0 In-Reply-To: <20090403050246.GM9870@mit.edu> References: <49CCCB0A.6070701@nokia.com> <9b1675090904021724t2fb0a671uc10d8e7bcba0bc5c@mail.gmail.com> <9b1675090904021728y35776377u327f2266d06e2f29@mail.gmail.com> <72dbd3150904021855v440f46a7oc21a7ed28fbfcb13@mail.gmail.com> <9b1675090904021905o7e0cec64lfe4a5372777908b6@mail.gmail.com> <72dbd3150904021919g5405ee40p100eacb085024941@mail.gmail.com> <9b1675090904021928k5a9948f9l8d93b6cbd5531720@mail.gmail.com> <72dbd3150904021958q7795dc62keb54d1fbfaa6abc7@mail.gmail.com> <20090403050246.GM9870@mit.edu> Date: Fri, 3 Apr 2009 11:05:16 -0700 Message-ID: <72dbd3150904031105v1020e836i61c5a4bc0ebe453@mail.gmail.com> Subject: Re: EXT4-ish "fixes" in UBIFS From: David Rees To: Theodore Tso , David Rees , "Trenton D. Adams" , Christian Kujau , Artem Bityutskiy , Linux Kernel Mailing List Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 2, 2009 at 10:02 PM, Theodore Tso wrote: > On Thu, Apr 02, 2009 at 07:58:17PM -0700, David Rees wrote: >> >> I've got a problematic server with 8GB RAM.  Even if set both to 1, >> that's 80MB and the crappy disks I have in it will often only write >> 10-20MB/s or less due to the seekiness of the workload.  That means >> delays of 5-10 seconds worst case which isn't fun. > > Well, one solution is data=writeback.  If you're confident your server > isn't going to randomly crash (i.e., it's on a UPS, and you're not > running unstable video drivers), that might be a solution.  It has > tradeoffs, though. Yeah, that's probably a good workaround for the server in question. I don't recall it ever crashing. > One thing which I'll probably implement is some patches to ext3 so > that when it's in data=writeback mode, it will use the same > replace-via-rename and replace-via-truncate hueristics that I added in > ext4 so that it will start an aysnchronous writeout on the rename() or > close() w/ truncate().  That should avoid existing files getting > corrupted when they are replaced right before the system crashes. I think that would be a welcome addition to the writeback mode of ext3. > People will still be better off moving to ext4, but for people who > aren't quite confident in ext4's stability yet and who want to stick > with ext3, maybe it's a good short-term solution.  Maybe > data=writeback with the rename hueristic would be a better default > than data=ordered for ext3. I've been waiting for Fedora to ship either the latest stable 2.6.28 or 2.6.29 kernel before putting any serious data on ext4 - from what I've seen it seems like those kernels should have the vast majority of stability bugs fixed in them. Last I remember reading the 2.6.27 doesn't quite have all the fixes due to difficulties in backporting those fixes to that kernel. -Dave