Appendix E: Other Potential Cluster Filesystems and Lock Arbitration Methods

Additional open source, or free, filesystem technologies that may be considered when building a shared data solution in a Linux enterprise environment include the following:

CODA

• Allows multiple file servers to store the same data. For the latest information, see http://www.coda.cs.cmu.edu (see the CODA FAQ "general" question, "How stable and usable is CODA?").

DRBD

• Mirrors a storage device at the block level over the network. A primary node has read/write access to the data, and when used in combination with the Heartbeat package (discussed in Part II of this book), a backup node has the ability to gain read/write access to the data when the primary node fails. For the latest information, see http://www.comp-lang.tuwien.ac.at/reisner/drbd.

Intermezzo

• Another distributed open source filesystem with great promise. Inter-mezzo was "deeply inspired" by the CODA filesystem and entered the Linux kernel at version 2.4.15. However, Intermezzo is not designed for high-performance write access to a single file or database by multiple cluster nodes. For the latest information, see http://www.inter-mezzo.org.

Lustre

• A cluster filesystem that is capable of supporting tens of thousands of nodes. For the latest information, see http://www.lustre.org.

Polyserve

• A high performance NAS cluster for Linux that uses a SAN for data storage (http://www.polyserve.com).

Oracle Cluster File System (CFS)

• Part of the Linux Single System Image (SSI) project. For the latest information, see http://ssic-linux.sourceforge.net.

Panasas

• For the latest information, see http://www.panasas.com.

V9fs

• For the latest information, see http://v9fs.sourceforge.net.

The Open Distributed Lock Manager (DLM) project

• This is a GNU open source project originally started at IBM that will currently work with a two-node Heartbeat configuration. The Open DLM package provides application programming interface (API) routines that will perform lock arbitration. You can then use these lock arbitration APIs if you are writing your own application to access the data. For the latest information, see http://oss.software.ibm.com/developerworks/projects/dlm.

Open Global File System (GFS)

• This used to be an open source project that turned into a product from the Sistana company that was then purchased by Red Hat. Somewhere along the line the open source version of GFS was revived, so now there are two projects: Open GFS and GFS. At the time of this writing information about GFS is available online at http://www.redhat.com/software/rha/gfs.