>I wonder if something as simple as "track the total bytes written to a >particular file while that file is currently open, once it exceeds x% of >the cache, bypass" would perform reasonably?
Is the write behavior necessarily this dependent on cache size alone? I'm speculating that cache state would be relevant. If I've got a large empty cache or mostly unused cache, do I get the same write performance as with an about-to-purge-I'm-full cache? Or might there be a dependency on the number/percentage of dirty chunks ... those have got to be flushed back to the fileserver before they can be reclaimed, so the worst case might be a large cache with lots of dirty chunks from lots of small files. I've only been "bothered" by the write performance limitations once or twice -- when continuously and rapidly writing/closing/opening an output file from an "indexer" into AFS filespace. Indexing software was proprietary, couldn't get vendor to change it .... so finally moved the output file outside of AFS -- automatically moved it back when the indexing was complete. It took a while to figure out what the bottleneck was, though, and it would by all means be great to have a reasonable bypass algorithm. Or even the ability to tag a file/directory/volume/partition as "don't cache." Which again presupposes the willingness to identify the file/directory/... ----- Original Message ----- From: "Neulinger, Nathan" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, February 17, 2003 4:24 PM Subject: RE: [OpenAFS] poor out of cache behavior on writing I wonder if something as simple as "track the total bytes written to a particular file while that file is currently open, once it exceeds x% of the cache, bypass" would perform reasonably? It wouldn't help the small cases. Another possible scenario would be assume bypass until the file has been read once. That would cause all initial creates to bypass, but later appends/edits would return to normal speed. ------------------------------------------------------------ Nathan Neulinger EMail: [EMAIL PROTECTED] University of Missouri - Rolla Phone: (573) 341-4841 Computing Services Fax: (573) 341-4216 > -----Original Message----- > From: Derrick J Brashear [mailto:[EMAIL PROTECTED]] > Sent: Monday, February 17, 2003 5:14 PM > To: [EMAIL PROTECTED] > Subject: Re: [OpenAFS] poor out of cache behavior on writing > > > On Mon, 17 Feb 2003, Paul Blackburn wrote: > > > You probably will get better data transfer from ftp-client > => ftp-server > > than a distributed filesystem. > > This, at least, is a protocol. scp is a hack, which is why > I'm reluctant > to use it. > > > When it comes to "uploading" large datafiles from machine > to machine, > > I now prefer using SSH's scp which shows me a progress bar and ETA. > > > > For most all other tasks, I like AFS which gives me other > capabilities > > unheard of in NFS. > > I wonder if we could find a sucker^H^H^H^H^H^Hgrad student to > figure out > ("guess") when to bypass the cache and when to use it, and > incorporate it > (at least as an option) in the clients. > > I know CITI has done cache-bypass stuff, but it used the > volume name (I > think) as a hint. > > > _______________________________________________ > OpenAFS-info mailing list > [EMAIL PROTECTED] > https://lists.openafs.org/mailman/listinfo/openafs-info > _______________________________________________ OpenAFS-info mailing list [EMAIL PROTECTED] https://lists.openafs.org/mailman/listinfo/openafs-info _______________________________________________ OpenAFS-info mailing list [EMAIL PROTECTED] https://lists.openafs.org/mailman/listinfo/openafs-info
