Summary

After having spent two chapters trying to diagnose and analyze the performance of different layers in the I/O stack, this chapter focused on the performance-tuning aspect of the I/O stack. Throughout this book, we’ve familiarized ourselves with the multi-level hierarchy of the I/O stack and built an understanding of the components that can impact the overall I/O performance.

We started this chapter by briefly going through the functions of the memory subsystem and how it can impact the I/O performance of a system. As all write operations are, by default, first performed in the page cache, the way the page cache is configured to behave can have a major say in an application’s I/O performance. We also explained the concept of direct I/O and defined some of the different parameters that can be used to tweak the write-back cache.

We also looked at the different tuning options when it comes to filesystems. Filesystems offer different mount options that can be...