“In 1994, Silicon Graphics Inc., of Mountain View, Calif., (SGI)
released a new journaled file system on IRIX, the company’s System
V-based version of UNIX. This advanced file system, called XFS,
replaced SGI’s old EFS (Extent File System) file system, which was
designed similar to the Berkeley Fast File System. Coordinating
with many other kernel developers, SGI is currently working to
tightly integrate the XFS file system with the Linux operating
system so that we can take advantage of the many benefits of XFS
over the current ext2 file system. This article discusses XFS and
its technical specifications.”
“XFS uses B+ trees extensively in place of the traditional
linear file system structure. B+ trees use a highly efficient
indexing method to index directory entries, manage file extents,
locate free space, and keep track of the locations of file index
information. As a result, reading file systems and retrieving
information from them happens quickly–without using large amounts
of system resources.”
“Currently, the XFS team is developing enhancements to the
Linux page cache so XFS can be tightly integrated with the Linux
kernel. This work is being done so XFS relies solely on the
page cache to store both file data and file system metadata.
This work can also be used to enhance other file systems to
improve overall system performance, because it is being developed
at a kernel level. These features will most likely be unavailable
until Linux 2.5, except as a part of XFS itself.”