Log rotation is a process that periodically archives, compresses, and deletes log files after a defined retention period. Without rotation, log files grow without limit, consume storage, and can in the worst case cause a system outage. In your ISMS, define retention periods for different log types considering compliance requirements (GDPR, industry regulations) and the need for forensic traceability. Typical periods range from 90 days for operational logs to several years for security-relevant protocols. Ensure that rotated logs are archived at a central, protected location.