Log-structured file system for Linux 2.6

Performance measurements

IOzone

IOzone is a file system benchmarking tool available from www.iozone.org capable of measuring wide variety of file system operations on many platforms. We have used it to test both single threaded and multithreaded performance of LFS (in both roll-forward and checkpoint recovery modes) and compare it to ext3. It is important to note that almost no cleaning was performed by LFS in these tests.

1. Single threaded measurements
   1. Measurements disregardig fsync
      1. LFS with roll-forward vs. ext3
      2. LFS with checkpoints vs. ext3
      3. Comparison of LFS modes
      4. 3D graphs of LFS with roll-forward
   2. Measurements including fsync
      1. LFS with roll-forward vs. ext3
      2. LFS with checkpoints vs. ext3
      3. Comparison of LFS modes
      4. 3D graphs of LFS with roll-forward
2. Multithreaded measurements

   In the following measurements, operations performed concurrently by 8 threads.

   1. Measurements disregardig fsync
      1. Comparison of LFS with roll-forward and ext3
      2. 3D graphs of LFS performance
   2. Measurements including fsync
      1. Comparison of LFS with roll-forward and ext3
      2. 3D graphs of LFS performance

File creation and removal

We have run and timed a few simple loops creating and deleting files in order to asses LFS metadata performance on both LFS and ext3. The results are available here,

Postmark

Postmark is a benchmark based on small file operations similar to those used on large mail servers and news servers. Our test run has shown superior LFS performance in these workloads.

Garbage collector overhead

The garbage collector overhead is one of the key aspects determining the overall LFS performance. Results of this test show what the overhead is under different disk utilizations and access patterns.