From: Dan Stromberg Subject: RE: NFS and tinygrams Date: Thu, 21 Oct 2004 12:56:15 -0700 Sender: nfs-admin@lists.sourceforge.net Message-ID: <1098388574.3601.248.camel@tesuji.nac.uci.edu> References: <482A3FA0050D21419C269D13989C611302B07E75@lavender-fe.eng.netapp.com> <1098386134.3601.209.camel@tesuji.nac.uci.edu> Mime-Version: 1.0 Content-Type: text/plain Cc: Dan Stromberg , Linux NFS Mailing List Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list2.sourceforge.net with esmtp (Exim 4.30) id 1CKj3D-0001zj-8z for nfs@lists.sourceforge.net; Thu, 21 Oct 2004 12:56:43 -0700 Received: from dcs.nac.uci.edu ([128.200.34.32] ident=root) by sc8-sf-mx1.sourceforge.net with esmtp (TLSv1:AES256-SHA:256) (Exim 4.41) id 1CKj3C-00039y-7E for nfs@lists.sourceforge.net; Thu, 21 Oct 2004 12:56:42 -0700 To: "Lever, Charles" In-Reply-To: <1098386134.3601.209.camel@tesuji.nac.uci.edu> 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: Here are our packet lengths with counts, over 10000 packets: count packet length 3 70 1 74 2 82 3 98 164 182 180 186 8827 190 76 202 407 286 52 4266 1 7418 284 8362 Does this look normal for a network with jumbo frames enabled transferring lots of mostly-large files? On Thu, 2004-10-21 at 12:15, Dan Stromberg wrote: > On Thu, 2004-10-21 at 11:56, Lever, Charles wrote: > > > A tinygram is a small packet. > > > > > > Many of the NFS packets I'm seeing are small - say about 200 > > > or 300 bytes. Then from time to time, there's a 7k packet, > > > like I'd like to see more of. > > > > do you know what's in the small packets? 200 to 300 bytes are typical > > of most NFS operations (not READ or WRITE). maybe your application is > > causing the client to generate lots of NFS requests, but only a few of > > them are WRITEs. > > This is the NFS portion of a 190 byte packet, that appears to be fairly > representative, taken from tethereal: > > Network File System > Program Version: 3 > V3 Procedure: READ (6) > file > length: 36 > hash: 0x3305e54e > type: unknown > data: 01000006007900411A00000000000000 > 001B8C1A000000000000000000057E72 > 00000000 > offset: 1484812288 > count: 8192 > > Most of the files in this filesystem are large (data from simulation > runs in netcdf format), but there certainly are some small ones. > > Right now, our application is rsync. But that may change later. > > > > Someone just told me that netapp servers can do intent-based > > > NFS. Do you concur? > > > > i've never heard of "intent-based NFS." can you explain what this > > means? > > I believe it means that you bundle a bunch of operations together into > one large packet, and the execution of later operations is contingent on > the success of earlier operations (or perhaps more generally, the exit > status of earlier operations - not sure). > > Lustre, I'm told, uses an intent-based protocol to speed up its > operations. > > The FC2 nfs implementation (kernel 2.6.8-1) has a structure named > "intent", which -might- only be used in NFS v4. > > There's some discussion of the data structure for intent-based NFS here: > > http://seclists.org/lists/linux-kernel/2003/May/6040.html > > Unfortunately, our AIX 5.1 machine does not support NFS v4. Anyone know > if AIX 5.3 does? I'll ask on an AIX mailing list too... > > > > > > > > On Thu, 2004-10-21 at 10:47, Lever, Charles wrote: > > > > what's a "tinygram" ? > > > > > > > > do you mean the NFS write requests aren't all "wsize" bytes? or do > > > > you mean the TCP layer is segmenting into small IP packets? > > > these are > > > > two separate layers, and do not interact. > > > > > > > > > -----Original Message----- > > > > > From: Dan Stromberg [mailto:strombrg@dcs.nac.uci.edu] > > > > > Sent: Thursday, October 21, 2004 1:05 PM > > > > > To: Linux NFS Mailing List > > > > > Cc: Dan Stromberg > > > > > Subject: [NFS] NFS and tinygrams > > > > > > > > > > > > > > > > > > > > We have a series of test transfers going, where we are > > > > > shuttling data from GFS->NFS V3 over UDP->NFS V3 over TCP->Lustre. > > > > > > > > > > On the NFS V3 over TCP link, we're seeing a lot of tinygrams, > > > > > despite having 8K NFS block sizes turned on, and jumbo > > > > > packets enabled (9000 byte MTU). > > > > > > > > > > The GFS machine runs Redhat 9, the first NFS server also runs > > > > > Redhat 9. > > > > > The machine copying from NFS to NFS is running AIX 5.1. The > > > > > machine copying NFS to Lustre is running RHEL 3. > > > > > > > > > > I didn't check on the packet sizes of the other legs of the > > > > > transfer. > > > > > > > > > > I've verified that we do have jumbo packets being used some > > > > > of the time, on that AIX 5.1 -> RHEL 3 hop. However, we're > > > > > still getting a pretty large percentage of tinygrams. > > > > > > > > > > Is there any way of cutting down on the tinygrams, to more > > > > > effectively utilize our large MTU? Is there perhaps any sort > > > > > of "intent based" packetizing in standard implementations of > > > > > NFS on Redhat 9, AIX 5.1, and/or RHEL 3? > > > > > > > > > > (Yes, we could short circuit the AIX 5.1 part of the > > > > > transfer, and that Would make things faster, but it Wouldn't > > > > > test what we need to test!) > > > > > > > > > > Thanks! > > > > > > > > > > -- > > > > > Dan Stromberg DCS/NACS/UCI > > > > > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------- > > > > > This SF.net email is sponsored by: IT Product Guide on > > > > > ITManagersJournal Use IT products in your business? Tell us > > > > > what you think of them. Give us Your Opinions, Get Free > > > > > ThinkGeek Gift Certificates! 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