From: Jake Gold Subject: Re: NFSv4 and client caching to local disk? Date: Mon, 31 Mar 2003 10:38:50 -0800 Sender: nfs-admin@lists.sourceforge.net Message-ID: <20030331103850.1f40a7f9.jake@dtiserv2.com> References: <6440EA1A6AA1D5118C6900902745938E07D55473@black.eng.netapp.com> <3E8835A3.D5E64144@moving-picture.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: Charles.Lever@netapp.com, nfs@lists.sourceforge.net Return-path: Received: from mail01.dtiserv2.com ([216.101.214.6]) by sc8-sf-list1.sourceforge.net with smtp (Exim 3.31-VA-mm2 #1 (Debian)) id 1904C9-0000rw-00 for ; Mon, 31 Mar 2003 10:39:45 -0800 To: James Pearson In-Reply-To: <3E8835A3.D5E64144@moving-picture.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: I am also extremely interested in something like this. I think the Zeus web server's model for in-memory caching would be great for NFS clients doing disk caching. Something like this would be great: cache_directory = /cache Directory where cache files are stored cache_files Size of the web server file cache (number of files) cache_small_file Maximum size of a 'small' file (bytes) (system page size) cache_large_file Minimum size of a 'large' file (bytes) cache_stat_expire Time for which the response of a stat() call is cached (seconds) cache_max_bytes Maximum size to reserve for cached files (bytes) (0 = no limit) cache_flush_interval Time after which unaccessed files are flushed from the cache (seconds) cache_cooling_time Integer any file modified in the last 'n' seconds is not cached cache_max_filename_length Integer filenames greater than this length aren't cached (Zero is no limit) I have a FAS940 with a cluster of Linux machines mounting _read-only_ volumes over NFSv3. My situation is the same as James Pearson's....those machines read large, rarely modified files, where memory caching doesn't help a whole lot. It would be very nice to be able to have my under-worked local disks take some of the load off the filer. Are there currently _any_ client-side NFS caching solutions (even something that requires some extra work)? Thanks in advance, Jake On Mon, 31 Mar 2003 13:33:39 +0100 James Pearson wrote: > "Lever, Charles" wrote: > > > > hi james- > > > > > I'm trying to find out more about 'cachefs' type file systems > > > that can > > > cache NFS data to a client's local disk - I've come across a > > > couple of > > > references that seem to indicate that this may be possible with NFSv4. > > > > > > Does (will?) the Linux NFSv4 client support this feature? > > > > Sun implemented cachefs on Solaris for earlier versions of NFS. > > it really has nothing to do with which version of NFS that is > > in use. > > I've briefly looked at this on IRIX clients some time ago - but we don't > have many IRIX boxes in use now. > > > there is sporadic interest in a cachefs on Linux, and i know of > > at least one generic prototype. a specific implementation of > > client-side disk caching that is available today is contained > > in the Linux OpenAFS client (known as the AFS cache manager). > > I have done some limited searching of the net for info and come across a > few attempts with earlier kernels - and I am aware of some the > issues/problems associated with doing this. > > > cachefs becomes rather more interesting when used in conjunction > > with NFSv4 file delegations -- that makes NFS behave in a fashion > > similar to AFS client-side disk caching with callbacks. > > My hopes were raised as the NFSv4 specs suggest that low level support > for client disk caches is available - rather than being a 'bolt-on' for > earlier versions - hence my question. > > > there currently is no explicit plan to implement cachefs by the > > team that is working on NFSv4 for Linux. a disk cache has > > rather limited usefulness compared to a memory cache. what is > > your application for it? > > Mainly for reading large files that don't change (much) - i.e. > effectively in a read-only mode. The total size of the required files is > greater than the clients memory size - in fact any disk caching of NFS > data doesn't necessarily need to survive a reboot of the client, so > caching NFS file system data to swap could be enough for my needs ... > > James Pearson > > > ------------------------------------------------------- > 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 > ------------------------------------------------------- This SF.net email is sponsored by: ValueWeb: Dedicated Hosting for just $79/mo with 500 GB of bandwidth! 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