XFS 3.1.1

XFS combines advanced journaling technology with full 64-bit addressing and scalable structures and algorithms. This combination delivers the most scalable high-performance filesystem ever conceived.

Features The Xfs Filesystem Provides The Following Major Features:

• Quick Recovery The XFS journaling technology allows it to restart very quickly after an unexpected interruption, regardless of the number of files it is managing. Traditional filesystems must do special filesystem checks after an interruption, which can take many hours to complete. The XFS journaling avoids these lengthy filesystem checks.


• Fast Transactions The XFS filesystem provides the advantages of journaling while minimizing the performance impact of journaling on read and write data transactions. Its journaling structures and algorithms are tuned to log the transactions rapidly. XFS uses efficient tree structures for fast searches and rapid space allocation. XFS continues to deliver rapid response times, even for directories with tens of thousands of entries.


• Massive Scalability XFS is a full 64-bit filesystem, and thus is capable of handling filesystems as large as a million terabytes. 263 = 9 x 1018 = 9 exabytes A million terabytes is thousands of times larger than most large filesystems in use today. This may seem to be an extremely large address space, but it is needed to plan for the exponential disk density improvements observed in the storage industry in recent years. As disk capacity grows, not only does the address space need to be sufficiently large, but the structures and algorithms need to scale. XFS is ready today with the technologies needed for this scalability. XFS also continues to evolve to match the capabilities of the hardware it is being deployed on. Efficiency when dealing with large amounts (terabytes) of main memory and hence large numbers of active files and large amounts of cached file data are areas demanding continual improvements. Extending XFS to improve performance on large NUMA machines is also an area of active research and development.


• Efficient Allocations XFS implements extremely sophisticated space management techniques. Efficiency in space management has been achieved through the use of variable sized extents, rather than the simple single-block-at-a-time mechanism of many other filesystems. XFS was the first filesystem to implement delayed space allocation for buffered writes, supports direct I/O, provides an optional realtime allocator, and is able to align allocations based on the geometry of the underlying storage device. The XFS allocator performs admirably in the presence of multiple parallel writers, and is renowned for its resistance to space fragmentation under such conditions.


• Excellent Bandwidth XFS is capable of delivering very close to the raw I/O performance that the underlying hardware can provide. XFS has proven scalability on SGI Altix systems of multiple gigabytes-per-second on multiple terabyte filesystems.