XFS: the workhorse
XFS is a high-performance journaling file system created by Silicon Graphics, Inc. for their IRIX workstations. XFS is particularly proficient at parallel I/O due to its allocation group based design. This enables extreme scalability of I/O threads, filesystem bandwidth, file and filesystem size when spanning multiple storage devices.
Key features of XFS include:
- Journaling: Like other journaling file systems, XFS keeps a log (journal) of file system changes before they are written to disk. This helps ensure data integrity in the event of a system crash or power failure, as the file system can use the journal to recover incomplete operations.
- Scalability: XFS is designed to handle large volumes and large files efficiently. It supports file systems as large as 16 EiB and individual file sizes up to 8 EiB, making it suitable for modern data centers and high-performance applications that require managing vast amounts of data.
- Parallel I/O: XFS is optimized for parallel I/O operations, which improves performance for applications with heavy read/write demands like databases or large media files.
- Extents-based Allocation: XFS uses extents (contiguous blocks of storage) to manage files, which reduces fragmentation and improves throughput when working with large files.
- Online Defragmentation: XFS supports online defragmentation, allowing for defragmentation of the file system without having to unmount it. This is particularly useful for maintaining performance on systems with minimal downtime.
- Dynamic Allocation: XFS supports dynamic inode allocation, meaning that inodes (the data structures used to store metadata about files) can be created as needed, improving the file system’s efficiency when dealing with a large amount of files.
- Data Integrity: In addition to journaling, XFS also provides checksumming of metadata, which helps ensure data integrity and detect corruption. This is important for environments where data reliability is critical.
- Efficient Space Management: XFS is known for its efficient space management. It uses techniques like delayed allocation and aggressive pre-allocation to minimize disk fragmentation and optimize disk space usage
XFS is the file system of choice when high throughput and performance are important. It's the file system of choice for storage arrays found in servers and NAS systems. It is a good choice for the backing storage for virtual machine environments and high availability database applications. While it lacks some of the advanced features found in other file systems (like snapshots or compression), it excels in areas such as scalability, performance, and data integrity. XFS is well-suited for applications requiring fast, reliable access to large datasets.
Areas that XFS does not perform well in is handling large amounts of small files, as it stays true to its data center and workstation roots. Another downside of XFS is that while it's easy to grow the file system, it is not (yet) possible to shrink it. XFS recovery, while reliable, can be more complex than other file systems in cases of severe corruption, and its repair tools are not as user-friendly as those for Ext4.