From: "Roger Heflin" Subject: RE: NFS tuning - high performance throughput. Date: Wed, 15 Jun 2005 14:52:10 -0500 Message-ID: References: <1118862823.22484.13.camel@seki.nac.uci.edu> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: "'M. Todd Smith'" , Return-path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.12] helo=sc8-sf-mx2.sourceforge.net) by sc8-sf-list2.sourceforge.net with esmtp (Exim 4.30) id 1DiduS-0007Az-0G for nfs@lists.sourceforge.net; Wed, 15 Jun 2005 12:50:48 -0700 Received: from host27-37.discord.birch.net ([65.16.27.37] helo=EXCHG2003.microtech-ks.com) by sc8-sf-mx2.sourceforge.net with esmtp (Exim 4.41) id 1DiduP-00049N-E8 for nfs@lists.sourceforge.net; Wed, 15 Jun 2005 12:50:47 -0700 To: "'Dan Stromberg'" In-Reply-To: <1118862823.22484.13.camel@seki.nac.uci.edu> Sender: nfs-admin@lists.sourceforge.net Errors-To: nfs-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: Discussion of NFS under Linux development, interoperability, and testing. List-Post: List-Help: List-Subscribe: , List-Archive: The mount/remount (unless you time how long it takes to unmount), will potentially still skew the write test, and the writes will still be happening for quite a while after the dd completes. Roger > -----Original Message----- > From: Dan Stromberg [mailto:strombrg@dcs.nac.uci.edu] > Sent: Wednesday, June 15, 2005 2:14 PM > To: Roger Heflin > Cc: 'M. Todd Smith'; nfs@lists.sourceforge.net; > strombrg@dcs.nac.uci.edu > Subject: RE: [NFS] NFS tuning - high performance throughput. > > > A bigger dd test should work - if you use about 3x your > physical memory, you'll probably be fine doing it that way. > > Another way that may work better in -some- cases, is to > umount the filesystem and re-mount it - except for warm > restartable filesystems. > > On Wed, 2005-06-15 at 10:28 -0500, Roger Heflin wrote: > > Make the dd test bigger, with 2x the memory size, 50% will be from > > cache and almost instanteous, with 4x the memory size, 25% will be > > from cache, bigger runs will get closer to actual reality, on the > > tests I do I run things 8x, but if you run 2x, 4x, 8x memory you > > should get a decent graph to give you an idea of what the > actual value > > is. > > > > Roger > > Atipa Technologies. > > > > > -----Original Message----- > > > From: nfs-admin@lists.sourceforge.net > > > [mailto:nfs-admin@lists.sourceforge.net] On Behalf Of M. > Todd Smith > > > Sent: Wednesday, June 15, 2005 9:47 AM > > > To: nfs@lists.sourceforge.net > > > Subject: Re: [NFS] NFS tuning - high performance throughput. > > > > > > Roger Heflin wrote: > > > > > > >Are you using the same dd test on the local machine test? > > > If so cache > > > >will be a major factor. > > > > > > > >Also, raid5 stripe size, bigger is almost always better, > I would do > > > >some testing with different strip sizes and see how it > affects the > > > >speed, I have never seen less than 32k be faster than 32k. > > > > > > > >Are you using md for the raid5 setup or something else > that has not > > > >been mentioned? > > > > > > > > Roger > > > > > > > > > > > Roger, > > > > > > I was told by a consultant we hired to help us with this that 5Gb > > > test files should be large enough to blow out the caches. > > > Looking back I realize that must have been when we only > had 2Gb RAM > > > in the machine .. > > > is there a better test I can use to check local rw > performance, as > > > well is there a formula or recommended way to calculate how big a > > > file you should rw to properly check local rw? > > > > > > I'll have to ask our soft eng who worked with the > consultant as to > > > why that particular stripe size was used. I believe we are using > > > md, we attempted to use LVM but ran into some problems > and had some > > > file inconsistencies that were unacceptable so had to back out of > > > it. > > > > > > Cheers > > > Todd > > > > > > -- > > > Systems Administrator > > > ---------------------------------- > > > Soho VFX - Visual Effects Studio > > > 99 Atlantic Avenue, Suite 303 > > > Toronto, Ontario, M6K 3J8 > > > (416) 516-7863 > > > http://www.sohovfx.com > > > ---------------------------------- > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------- > > > SF.Net email is sponsored by: Discover Easy Linux Migration > > > Strategies from IBM. Find simple to follow Roadmaps, > straightforward > > > articles, informative Webcasts and more! Get everything > you need to > > > get up to speed, fast. > > > http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click > > > _______________________________________________ > > > NFS maillist - NFS@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/nfs > > > > > > > > > > > ------------------------------------------------------- > > SF.Net email is sponsored by: Discover Easy Linux Migration > Strategies > > from IBM. Find simple to follow Roadmaps, straightforward articles, > > informative Webcasts and more! Get everything you need to get up to > > speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click > > _______________________________________________ > > NFS maillist - NFS@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/nfs > > > ------------------------------------------------------- SF.Net email is sponsored by: Discover Easy Linux Migration Strategies from IBM. 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