This talk provided a comprehensive update on the state of local file systems in the Linux kernel as of early 2013, focusing on three major file systems: XFS, ext4, and Btrfs. The presentation examined the evolving challenges facing modern file systems, including scalability demands driven by increasing storage capacities and computing parallelism, reliability concerns for massive file systems, and adaptation to new storage technologies like SSDs, thinly provisioned storage, and hierarchical storage systems. The talk highlighted how each file system was addressing these challenges through different approaches, from XFS’s delayed logging and metadata checksumming to ext4’s extent status tree and bigalloc features, while noting that Btrfs, though still under heavy development, offered promising design foundations with features like comprehensive checksumming and online scrubbing capabilities.

Key Takeaways:

  • Scalability challenges are paramount as single drives reach 4TB capacity, requiring file systems to handle both larger storage and increased parallelism from multi-threaded workloads, with the traditional I/O stack designed for high-latency, low-IOPS scenarios needing modernization
  • XFS emerged as the premier choice for large-scale deployments with hundreds of terabytes, benefiting from delayed logging improvements and new metadata checksumming capabilities
  • Reliability improvements across all three file systems focused on metadata checksumming for early error detection and faster, more memory-efficient repair tools, though Btrfs’s fsck utility remained incomplete
  • Maintainability concerns highlighted the complexity of managing multiple file systems with incompatible tooling, emphasizing the value of centralized management tools like System Storage Manager