Nir Tzachar recently announced the availability of a new filesystem referred to as srFS, or the "Self-Stabilizing Replication File System". According to the project's home page:
"srFS is a global file system designed to be distributed geographicly over multiple locations and provide a consistent, high available and durable infrastructure for information."
Among the available publications about srFS, an implementation report [pdf] describes a self stabilizing system as "a system that can automatically recover following the occurrence of (transient) faults. The idea is to design a system which can be started in an arbitrary state and still converge to a desired bahavior." The project is divided into two components, a kernel module for the stable 2.4 kernel, and a user-space caching daemon written in Java, communicating with each other via a character device. Nir's full announcement email follows.
From: Nir Tzachar [email blocked] To: linux-fsdevel Subject: srfs - a new file system. Date: Mon, 20 Oct 2003 11:12:07 +0200 (IST) hello all. We're proud to announce the availability of a _proof of concept_ file system, called srfs. ( http://www.cs.bgu.ac.il/~srfs/ ). a quick overview: [from the home page] srfs is a global file system designed to be distributed geographicly over multiple locations and provide a consistent, high available and durable infrastructure for information. Started as a research project into file systems and self-stabilization in Ben Gurion University of the Negev Department of Computer Science, the project aims to integrate self-stabilization methods and algorithms into the file (and operation) systems to provide a system with a desired behavior in the presence of transient faults. Based on layered self-stabilizing algorithms, provide a tree replication structure based on auto-discovery of servers using local and global IP multicasting. The tree structure is providing the command and timing infrastructure required for a distributed file system. The project is basically divided into two components: 1) a kernel module, which provides the low level functionality, and disk management. 2) a user space caching daemon, which provide the stabilization and replication properties of the file system. these two components communicate via a character device. more info on the system architecture can be find on the web page, and here: http://www.cs.bgu.ac.il/~tzachar/srfs.pdf We hope some will find this interesting enough to take for a test drive, and wont mind the latencies ( currently, the caching daemon is a bit slow. hopefully, we will improve it in the future. ) anyway, please keep in mind this is a very early version that only works, and keeps the stabilization properties. no posix compliance whatsoever... the code contains several hacks and design flaws that we're aware of, and probably many that we're not... so please be gentle ;) if someone found this interesting, please contact us with ur insights. cheers, the srfs team. p.s I would like to thank all members of this mailing list (fsdevel), for ur continual help with problems we encountered during the development. thanks guys (and girls???). ======================================================================== nir.
From: Eric Sandall [email blocked] Subject: Re: srfs - a new file system. Date: Mon, 20 Oct 2003 14:00:38 -0700 This sounds fairly similar to Coda, which is already in development and use. -sandalle  http://www.coda.cs.cmu.edu/ -- PGP Key Fingerprint: FCFF 26A1 BE21 08F4 BB91 FAED 1D7B 7D74 A8EF DD61 http://search.keyserver.net:11371/pks/lookup?op=get&search=0xA8EFDD61 -----BEGIN GEEK CODE BLOCK----- Version: 3.12 GCS/E/IT$ d-- s++:+>: a-- C++(+++) BL++++VIS>$ P+(++) L+++ E-(---) W++ N+@ o? K? w++++>-- O M-@ V-- PS+(+++) PE(-) Y++(+) PGP++(+) t+() 5++ X(+) R+(++) tv(--)b++(+++) DI+@ D++(+++) G>+++ e>+++ h---(++) r++ y+ ------END GEEK CODE BLOCK------ Eric Sandall | Source Mage GNU/Linux Developer [email blocked] | http://www.sourcemage.org/ http://eric.sandall.us/ | SysAdmin @ Inst. Shock Physics @ WSU http://counter.li.org/ #196285 | http://www.shock.wsu.edu/ ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.
From: Nir Tzachar [email blocked] Subject: Re: srfs - a new file system. Date: Tue, 21 Oct 2003 14:07:04 +0200 (IST) > > This sounds fairly similar to Coda, which is already in development and use. > not at all. coda is not self stabilizing at all. srfs is also a totally distributed file system -> see the doc. bye ======================================================================== nir.