From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Dungan Subject: Re: FS directly on top of dm devices? Date: Fri, 17 Apr 2009 08:55:18 -0700 Message-ID: <49E8A666.9060608@gps.caltech.edu> References: <49E7C4A6.3080301@gps.caltech.edu> <7bc80d500904161747n588b5b27v54b6c346ecd824d7@mail.gmail.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <7bc80d500904161747n588b5b27v54b6c346ecd824d7@mail.gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids Stripe alignment was the benefit we were thinking as well. These devices will be used for ext3 file systems that will store a mix of file sizes and types that are accessed by user-written and executed applications on an HPC cluster. It is difficult to tune the file system or the underlying SAN LUNs for such a mix, so we are choosing our best estimate for general i/o. It is comforting to know that others are using no partitioning. Thanks. Christopher Chen wrote: > I run md over mpath dm'd devices, without partitioning. Of course, I > use dm-multipath to reach individual disks in a JBOD with two FC-AL > loops. > > Lots of people like to do this to preserve stripe alignment. > > I also use LVM, with the metadatasize option on creation of the PV, to > preserve stripe alignment. > > Do you have a specific application in mind, like a database? > > On Thu, Apr 16, 2009 at 4:52 PM, Scott Dungan wrote: > >> We recently had an engineer from a large storage vendor suggest that we make >> our file systems directly onto the multipathed devices without first >> creating underlying partitions or using LVM. Having not run with this >> method in production before, we would like to gather as much information as >> possible first. Initial searches for documentation on this method has >> produced few results, short of a Suse/Novell document from 2005 under >> section 4: >> >> http://support.novell.com/techcenter/sdb/en/2005/04/sles_multipathing.html >> >> Does anyone have any experience with this or can point us to more >> documentation. thoughts or recommendations? >> >> Thanks, >> >> -- >> >> Scott A Dungan >> >> >> -- >> dm-devel mailing list >> dm-devel@redhat.com >> https://www.redhat.com/mailman/listinfo/dm-devel >> >> > > > > -- Scott A Dungan Systems Administrator GPS Division California Institute of Technology Phone: (626) 395-3170 Fax: (626) 585-1917