Tuesday, April 14th 2026
How we caught a silent IO storm before it hit production
A sysctl setting that worked fine for years caused over 500 MB/s of disk writes after migrating to Debian 12. MariaDB stalled on pending IO, Redis complained about slow fsync, and RBD-backed storage ground to a halt. The culprit: cgroup v2 changes how the kernel divides dirty page budgets across containers.
