Disk I/O bottlenecks in GitHub Actions

When your CI pipelines are slow, you can only optimize so much. Bottlenecks in CPU, Network, Memory, and Disk I/O can all contribute to slow CI pipelines. Let's take a look at how disk I/O can be a bottleneck in GitHub Actions. Disk I/O bottlenecks are easy to overlook when analyzing CI pipeline performance, but tools like iostat and fio can help shed a light on what might be slowing down your pipelines more than you know. GitHub offers different hosted-runners with a range of specs, but for this test we are using the default ubuntu-22.04 runner in a private repository, which does give us an additional 2 vCPUs but does not alter the disk performance. How to monitor disk performance Getting a baseline benchmark from a tool like fio is useful for comparing the relative disk performance of different runners. However, to investigate if you are hitting disk I/O bottlenecks in your CI pipeline, it is more useful to monitor disk performance during the pipeline execution. We can use a too ... Read full article.