From: Eric Sandeen Subject: Re: ext4 settings in an embedded system Date: Fri, 16 Nov 2012 09:56:44 -0600 Message-ID: <50A6623C.6050601@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: "Ohlsson, Fredrik (GE Healthcare, consultant)" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:9898 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752528Ab2KPP4s (ORCPT ); Fri, 16 Nov 2012 10:56:48 -0500 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On 11/14/12 4:41 AM, Ohlsson, Fredrik (GE Healthcare, consultant) wrote: > Hi, > I would like to have advice regarding features and options. > I am working with an embedded system equipped with an IDE Flash Disk > and the ext4 filesystem. I have identified 3 problems that I would > like to solve in our product. The power is abruptly turned off from > time to time, this has sometimes resulted in broken Superblock > (inode8) and empty files with size 0 bytes. It also happens that file > changes is not committed to disk even if minutes pass before a power > loss. This is very undesirable and expensive in our case, we are > searching for a solution or a workaround to the problems. > List with my problems I like to solve: > 1. Broken Superblock (inode8). > 2. Empty files, size 0. > 3. Very long auto commit times, several minutes with default settings. > > > Is ext4 a bad choice for an embedded system with I 1Gb IDE Flash Disk > and Debian 2.6.32-5-686? Should we change filesystem? > > I am planning to set the mount flags: barrier=1, commit=1 and > data=journal, is this the way to go with an embedded system and ext4? When you say "with barrier=1", were you using barrier=0 (or "nobarrier") before? If you have disabled barriers explicitly, just start with re-enabling them. If your software is doing all the right data integrity syscalls, then that is probably enough. -Eric > Is there more ext4 options/settings I can use to get an embedded > system reliable when a power loss occurs? > > Best Regards > > Fredrik Ohlsson > Software Engineer > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >