From: Bogdan Costescu Subject: Re: NFSv4 and client caching to local disk? Date: Wed, 2 Apr 2003 13:27:20 +0200 (CEST) Sender: nfs-admin@lists.sourceforge.net Message-ID: References: <3E89EF08.2050401@anim.dreamworks.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Jake Gold , James Pearson , , Return-path: Received: from mail.iwr.uni-heidelberg.de ([129.206.104.30]) by sc8-sf-list1.sourceforge.net with esmtp (Exim 3.31-VA-mm2 #1 (Debian)) id 190gP4-0002jB-00 for ; Wed, 02 Apr 2003 03:27:38 -0800 To: Skottie Miller In-Reply-To: <3E89EF08.2050401@anim.dreamworks.com> Errors-To: nfs-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Id: Discussion of NFS under Linux development, interoperability, and testing. List-Unsubscribe: , List-Archive: On Tue, 1 Apr 2003, Skottie Miller wrote: > We do the caching to compute-node local disk, via the applications when > we can. But two things often make that difficult: (1) the working set > of the cached data is larger than the compute-note local disk, Ah, so you define now a working set which is a subset of the whole data set. In this case I would say that you can't win in any situation; it's similar to a process that needs memory larger than RAM and has to use the disk - either the OS does swapping or the process itself writes parts of its memory to the disk, but it has to be done continuously as the process jumps through memory - the disk is used in any case and the performance is lowered... Buy larger disks :-) > (2) we don't own all the applications. Yes, obviously this is a problem and can only be solved if you are a big enough customer for the software company :-) But there might be some other problem: if the data set that is mostly read only is needed on most or all clients, updating it on the server will generate in a very short time a storm of requests for transfers of the new content. If you are using some blind OS level caching, this will create a big load on the server or network congestion because most or all clients will try to get the new data. With application level caching you might do nice stuff like using some priority lists, using one client that already got the data to send it to another client, etc. -- Bogdan Costescu IWR - Interdisziplinaeres Zentrum fuer Wissenschaftliches Rechnen Universitaet Heidelberg, INF 368, D-69120 Heidelberg, GERMANY Telephone: +49 6221 54 8869, Telefax: +49 6221 54 8868 E-mail: Bogdan.Costescu@IWR.Uni-Heidelberg.De ------------------------------------------------------- This SF.net email is sponsored by: ValueWeb: Dedicated Hosting for just $79/mo with 500 GB of bandwidth! No other company gives more support or power for your dedicated server http://click.atdmt.com/AFF/go/sdnxxaff00300020aff/direct/01/ _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs