Return-Path: linux-nfs-owner@vger.kernel.org Received: from mailgw1.uni-kl.de ([131.246.120.220]:48225 "EHLO mailgw1.uni-kl.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751131Ab2AZMcA (ORCPT ); Thu, 26 Jan 2012 07:32:00 -0500 Message-ID: <4F2147BA.6030607@itwm.fraunhofer.de> Date: Thu, 26 Jan 2012 13:31:54 +0100 From: Bernd Schubert MIME-Version: 1.0 To: Chuck Lever CC: lsf-pc@lists.linux-foundation.org, linux-fsdevel , Linux NFS Mailing List , linux-scsi@vger.kernel.org, Sven Breuner Subject: Re: [LSF/MM TOPIC] end-to-end data and metadata corruption detection References: <38C050B3-2AAD-4767-9A25-02C33627E427@oracle.com> In-Reply-To: <38C050B3-2AAD-4767-9A25-02C33627E427@oracle.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: On 01/17/2012 09:15 PM, Chuck Lever wrote: > Hi- > > I know there is some work on ext4 regarding metadata corruption > detection; btrfs also has some corruption detection facilities. The > IETF NFS working group is considering the addition of corruption > detection to the next NFSv4 minor version. T10 has introduced > DIF/DIX. > > I'm probably ignorant of the current state of implementation in > Linux, but I'm interested in understanding common ground among local > file systems, block storage, and network file systems. Example > questions include: Do we need standardized APIs for block device > corruption detection? How much of T10 DIF/DIX should NFS support? > What are the drivers for this feature (broad use cases)? > Other network file systems such as Lustre already use their own network data checksums. As far as I know Lustre plans (planned?) to use underlying ZFS checksums also for network transfers, so real client-to-disk (end-to-end) checksums. Using T10 DIF/DIX might be on their todo list. We from the Fraunhofer FhGFS team would like to also see the T10 DIF/DIX API exposed to user space, so that we could make use of it for our FhGFS file system. And I think this feature is not only useful for file systems, but in general, scientific applications, databases, etc also would benefit from insurance of data integrity. Cheers, Bernd -- Bernd Schubert Fraunhofer ITWM