Running Keycloak on a resource-constrained Linux VPS can lead to severe performance bottlenecks and out-of-memory crashes. Since Keycloak migrated to the Quarkus runtime, optimizing memory consumption has become both highly efficient and accessible. This comprehensive guide explores actionable Quarkus tuning strategies, JVM configurations, and database connection pooling adjustments to reduce Keycloak's memory footprint to under 512MB without sacrificing stability.