From: Artem Bityutskiy Subject: Re: ext4 settings in an embedded system Date: Thu, 15 Nov 2012 12:38:47 +0200 Message-ID: <1352975927.2221.23.camel@sauron.fi.intel.com> References: <1352968933.2221.16.camel@sauron.fi.intel.com> Reply-To: dedekind1@gmail.com Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-DNJ2HylXlMreOVyaHHdd" Cc: "Ohlsson, Fredrik (GE Healthcare, consultant)" , linux-ext4@vger.kernel.org To: Andrey Sidorov Return-path: Received: from mga02.intel.com ([134.134.136.20]:48232 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992967Ab2KOKiI (ORCPT ); Thu, 15 Nov 2012 05:38:08 -0500 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: --=-DNJ2HylXlMreOVyaHHdd Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2012-11-15 at 13:01 +0300, Andrey Sidorov wrote: > On Thu, Nov 15, 2012 at 12:42 PM, Artem Bityutskiy = wrote: >=20 > > We conducted some 3 years ago. Results were quite good for ext4 - in > > many cases it could recover without a need to run ckfs.ext4, sometimes > > it was not mountable, but ckfs.ext4 helped. > > > > On the opposite, ext3 constantly required ckfs.ext3, and sometimes died > > so badly that even ckfs.ext3 could not recover it. >=20 > We ran about 6000 cycles of power resets with linux 2.6.37. The test > was to run 3 tar processes unpacking linux kernel archive and power > off after about 15 seconds. There were only 3 failures when file > system couldn't be mounted, but that was due to HDD failure > (unreadable sector in journal area). e2fsck successfully recovered > those corruptions. As for software itself, there was no single issue > and we never needed to run fsck after power loss. So I'd say that ext4 > is very tolerant to power losses at least in 2.6.37 assuming barriers > and ordered data mode. I however understand this test is quite basic > and any way results can be different for different kernels. Very different experience indeed, shoes that everyone has to conduct own power-cut tests in own system. I did not say that we were running on eMMC. --=20 Best Regards, Artem Bityutskiy --=-DNJ2HylXlMreOVyaHHdd Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAABAgAGBQJQpMY3AAoJECmIfjd9wqK0GmcQAIz4z+mRYXGHtVanvXbQlRjV d7tW2amFQ02BX08aNndWhvvN22CayPYcyxZuH1tTkbgBivhq6G2TSobXkCrW72yL BraSaAIcCK/GK9mW3jNKKzhnutkbqHhPkDucYsq2l4Za5SrrYn2ukPgdo8vCNr1d 3vVRm3fUDgDi8hubYXWr6ylrFLPusJc9sW/VitBbp5Az2zv8/wU3Ljpb+Hp0omqn Y1x42sDGLA8/UPlnPK3C0FydfDNAdvZ8cXGw1SA7htGCPzOQFZiDA4ZYQEttKJ+g YTvSTDdBVtGPn4N0sUKlrnjV3aDl1AZAVl3DgmBc1+9SXftP0PVeI42F7wrFLhAT AxovFfAXWyDq600qjyDIbvaCCwjEB0+dDOf7lq/CNb3AQGJ8RxnL1nbiXJ5JfFTm ykoeyuWnmvKe8bO3VmA83v52IXk9Lzuvqc2+SCBZvMuSlA8sKzjjJY8Lqo1z67DD y7cJtXwmXtbK3pzi1vBH+84LxFlh3eFTcrFm/iqQ97iIXV/fwQuFn/FdFTB7C24Z ynkoRq3AeY1qWG9WIOXUvpODFYJRulQ3jXCJ/rDMD3kexJC0z8CoRbVl8Fdmbbh1 ur/vKTDm4F79lV2UBVsLyymtEF7K8TqbHBake/+3/xyaTdP4p93R6f0kYNecvhRe V10vrkDmcPVGjezToDUK =Vsjn -----END PGP SIGNATURE----- --=-DNJ2HylXlMreOVyaHHdd--