AU-4 Audit log storage capacity
Requires audit log storage to be sized and allocated against the retention requirements the organization has set, so that logging capacity does not run out and records are not lost before their retention period ends.
4
artefacts
3
held by a system
1
at each review
easy
to go live
SIEM / log platform
where the evidence lives
teal = a system already holds it · olive = produced at each review
system holds itEvidence a system already holds
- Capacity calculation linking log volume and retention period to allocated storage · SIEM / log platform
- Storage utilisation trend for the logging platform · SIEM / log platform
- Alert configuration for approaching capacity limits · SIEM / log platform
periodic reviewEvidence produced at each review
- Evidence of headroom or expansion action taken when growth increased · Policy repository / GRC workspace
governing documentDocuments that govern the control
none for this control
First move
Automate the pull from your SIEM / log platform. Retention and alert rules exported from the SIEM; review evidence is the closed-alert record with reviewer and time.
Common gaps auditors find
- Capacity sized at deployment and never revisited as log volume grew
- Overflow silently overwrites the oldest records rather than raising an alert
- Local device buffers overwrite within hours and forwarding failures go unnoticed
Do this for your whole sheet
Paste the rows you run your controls from and get this mapping for every control at once, with the periodic-review ones flagged and a first move per row. No account for the first run.
Build my evidence sheetAU-3 Content of audit records · AU-5 Response to audit logging process failures