(Illustration by Gaich Muramatsu)
On Fri, Sep 21, 2001 at 11:09:33AM +0800, Xuefeng wrote: > I am wondering how is the Coda project now. Is it still an actively > participated Open-source project among Internet community? There definitely is a community of active Coda users, I don't know about the Internet community in general, Coda has it's unique niche among network and distributed file systems and most people out there probably don't have a want or direct need for Coda's features. The kernel part of Coda is also used by several other projects as a convenient and reasonably portable way of implementing UserFS type file systems. > How does it compare with other open-source DFS projects, such as > Intermezzo and others? Coda doesn't use perl for the userspace cache-manager. No really, InterMezzo is the brain-child of Peter Braam, who was the Coda project leader for several years. It's goals were to provide 90% of the Coda functionality in 10% of the code. The goal has I believe shifted a bit more towards providing a reliable filesystem for clusters, although that might be another project Peter has been working on. I haven't played with InterMezzo myself, so I can't really tell you what features is does or doesn't have. However, it should be quite a bit faster, because it's kernel module is designed to really minimize the number of upcalls to userspace by among others keeping a log of write operations at the kernel level and the kernel manages access to the cached files instead of the userspace manager. Upcalls require at least 2 context switches so they are typically quite expensive and these design differences should vastly improve InterMezzo's performance on directory operations and file opens/closes. Actual file read/write performance (once the file is opened) should be the same for both Coda and InterMezzo as both redirect these operations directory to the cached files without having to make upcalls to userspace. This btw. is also the reason why Coda doesn't support a hard cache size limit, we only get to see the size of the file after the application is done writing and closes the file. JanReceived on 2001-09-21 15:14:33