GitHub Availability Report: January 2024

In January, GitHub experienced three notable incidents affecting service performance. On January 9, an upgrade to hosts led to reduced connection capacity, resulting in elevated latency and a notable percentage of request failures, which was resolved by adjusting connection limits and enhancing monitoring. On January 21, issues with compute and storage resources disrupted GitHub Codespaces, particularly affecting customers in East US and West Europe, until normal operations resumed after several hours, prompting efforts to enhance alerting and resiliency. The incident on January 31 involved an infrastructure change for IPv6 enablement that inadvertently caused request blocks due to the mishandling of IPv4-mapped IPv6-compatible addresses, leading to a minor error rate and necessitating improvements in testing and monitoring to prevent similar issues.