The CXFS file system (Clustered XFS) is a proprietary shared disk file system designed by Silicon Graphics (SGI) specifically to be used in a storage area network (SAN) environment.

CXFS
Developer(s)Silicon Graphics Inc.
Full nameCXFS
Introduced1994; 30 years ago (1994) with IRIX v5.3
Structures
Directory contentsB+ trees
File allocationextent based
Limits
Max volume size17 exabytes
Max file size8.5 exabytes
Max filename length255 bytes
Allowed filename
characters
All bytes except NUL
Features
Dates recordedYes
ForksYes (called extended attributes)
File system
permissions
Yes
Transparent
compression
No
Transparent
encryption
No (provided at the block device level)
Other
Supported
operating systems
Server: IRIX, Linux, Clients: IRIX, Solaris, Linux, Mac OS X, AIX, Windows

A significant difference between CXFS and other shared disk file systems is that data and metadata are managed separately from each other. CXFS provides direct access to data via the SAN for all hosts which will act as clients. This means that a client is able to access file data via the fiber connection to the SAN, rather than over a local area network such as Ethernet (as is the case in most other distributed file systems, like NFS). File metadata however, is managed via a metadata broker. The metadata communication is performed via TCP/IP and Ethernet.

Another difference is that file locks are managed by the metadata broker, rather than the individual host clients. This results in the elimination of a number of problems which typically plague distributed file systems.

Though CXFS supports having a heterogeneous environment (including Solaris, Linux, Mac OS X, AIX and Windows), either SGI's IRIX Operating System or Linux is required to be installed on the host which acts as the metadata broker.

See also

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