SC-6 asks you to protect the availability of resources by allocating them in a way you define, using priorities, quotas or other mechanisms. NIST says priority protection stops lower priority processes from delaying or interfering with the system that serves higher priority ones. Quotas stop users or processes from taking more than a set amount.
800-53 binds federal systems and contractors. For the rest of us it is a tidy way to describe noisy neighbor and runaway job protection.
What it means in practice
Every shared platform has a resource a greedy workload can exhaust: CPU, memory, disk, database connections, API calls, queue depth. The control asks you to decide who gets protected first and to enforce limits so one actor cannot take everything.
Evidence to collect
- Resource quotas and limits from your orchestrator or cloud account.
- API rate limit configuration per customer or key.
- Priority class or queue priority definitions.
- An incident or load test where a limit actually triggered.
Common gaps
Limits set on compute but not on databases. Batch jobs that share a pool with customer facing requests. Quotas that exist but are never reviewed after growth.
How to implement it
List the shared resources, assign priorities, set a default limit, and alert when anyone nears it. Separate batch work from production traffic.
Quick check
What is the difference between a priority and a quota?
A priority decides who is served first. A quota caps how much one user or process may take.
