From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Chow Subject: Re: Help!About MD on shared storage. Date: Tue, 05 Aug 2003 14:42:12 +0800 Sender: linux-raid-owner@vger.kernel.org Message-ID: <3F2F51C4.2050301@shaolinmicro.com> References: <1060018828.5102.78.camel@persist.az.mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: To: sdake@mvista.com Cc: hufh@Lenovo.com, linux-raid@vger.kernel.org List-Id: linux-raid.ids > > >Note that the same thing can be done using a configuration file per node >and using mdadm to only start the RAID volumes needed. This is the >methodology recommended by RAID maintainer, Neil Brown, however, I find >it difficult to setup which is why I proposed the patch. He could >probably provide more info on that methodology or there is a discussion >in the archives. > >If I ever get some time, I plan to implement shared access to the same >RAID volume for usage in a clustered filesystem application such as GFS. > If it really happens, every writes to the RAID will need to be synced . Since fs assumes the underlying block device is synced instead of async like md . This has been an issue of using md on cluster environment which calling sync only sync fs->block buffers and md buffers are not gaurantee to be synced. I am not sure how much performnace drawback will cause if every write to md must be synced and wait for return for the underlying real block device. Any ideas? David