CP-6: Alternate Storage Site

To meet the cp-6: alternate storage site requirement, you must designate a separate location (physical or cloud) to store system backups and put agreements in place so you can store and retrieve backups during an outage. Operationally, that means selecting an alternate storage site, defining access and retrieval procedures, and retaining evidence that backups are actually recoverable. ¹

Key takeaways:

• CP-6 expects a real, usable alternate storage location for backup media and data, not a paper-only plan. ¹
• You need agreements (internal or third-party) that explicitly permit storage and retrieval under adverse conditions. ¹
• Auditors will look for operational proof: backup inventories, replication/config screenshots, access paths, and restore test evidence tied to the alternate site.

CP-6 sits in the Contingency Planning (CP) control family in NIST SP 800-53 Rev. 5 and addresses a frequent failure mode in incident response: backups exist, but they’re co-located with the primary environment or blocked by contractual, access, or process constraints. CP-6 forces you to answer a simple question: “If the primary site is down or inaccessible, where are our backups, and can we retrieve them fast enough to support recovery?”

For a Compliance Officer, CCO, or GRC lead, CP-6 is one of those controls that becomes “real” only when you connect it to specific systems, a specific storage architecture, and specific operating procedures owned by identifiable teams. It also intersects with third-party risk management because many organizations satisfy CP-6 with a cloud provider, managed backup provider, colocation facility, or offsite vaulting service. That means contractual language, service descriptions, and access methods become audit evidence, not just procurement paperwork.

This page translates the requirement into concrete actions, artifacts, and audit-ready proof so you can implement CP-6 quickly and defend it during assessment. ²

Regulatory text

Excerpt: “Establish an alternate storage site, including necessary agreements to permit the storage and retrieval of system backup information; and” ¹

Operator interpretation (what you must do):

1. Pick an alternate storage site that is not the same failure domain as the primary site (for example, separate facility, separate cloud region/account, separate storage tenancy, or an offsite vaulting provider).
2. Put agreements in place (contracts, intercompany agreements, MOUs, SLAs, or documented internal service commitments) that explicitly allow you to store backups there and retrieve them during an event.
3. Make it operational with documented procedures, access paths, and recurring proof that backups are present and recoverable from the alternate site.

The control text is short, but auditors treat it as an operational dependency: if your alternate storage site cannot be accessed in practice, you have not met the requirement. ¹

Plain-English interpretation of the requirement

CP-6 means: your backups must survive a primary-site disruption and remain retrievable. “Alternate storage site” is about resilience against realistic constraints: building outage, ransomware encrypting local backups, cloud account lockout, regional outage, or a third party that refuses emergency access because the contract is vague.

In practice, a compliant implementation has:

• A named alternate storage location mapped to each in-scope system’s backup sets.
• Clear “break glass” retrieval steps with assigned roles.
• A paper trail showing your organization has the right to access the backups when it matters (including after-hours and during disputes).

Who it applies to (entity and operational context)

CP-6 applies most directly to:

• Federal information systems, and
• Contractor systems handling federal data (including service providers supporting federal missions or processing federal information). ¹

Operationally, you should treat CP-6 as in-scope for:

• Systems with defined recovery objectives (even if those objectives are set internally).
• Core identity services, security tooling, and configuration repositories needed to rebuild systems.
• Backup platforms themselves (backup servers, backup SaaS, backup storage accounts).
• Any third party that hosts, stores, or can restrict access to your backup data.

What you actually need to do (step-by-step)

Step 1: Define scope and control ownership

• Assign a control owner (often Infrastructure, Security Engineering, or IT Operations) and a GRC point-of-contact who maintains evidence and coordinates assessments.
• Enumerate in-scope systems and classify backup types: database, file, VM image, SaaS export, configuration-as-code repos, keys/secrets (if applicable).

Deliverable: CP-6 control implementation statement mapped to systems and owners.

Step 2: Choose an alternate storage design that avoids shared failure

Pick a pattern that fits your architecture:

Pattern	What it looks like	Typical audit concern
Offsite physical storage	Tape/drive vaulting, secure facility	Chain of custody, retrieval time, access authorization
Cloud cross-region storage	Backups replicated to another region	Same account compromises, IAM misconfig blocks retrieval
Cross-account / separate tenancy	Backups in a distinct account/subscription	Contract and access workflow between accounts
Managed backup provider	Third party stores backups	Contract language and emergency retrieval rights

You don’t need the most complex design. You need one that is documented, reachable, and tested.

Step 3: Put “necessary agreements” in writing (this is the CP-6 trap)

For third parties, ensure the agreement set (MSA/SOW/SLA/Order Form) covers:

• Right to store backup information at the alternate site.
• Right to retrieve/export backups on demand, including during incidents and after termination (as applicable to your arrangement).
• Access method (portal, API, support ticket) and any identity proofing requirements.
• Support expectations for emergency restores (who does what).
• Data handling terms that match your data sensitivity.

For internal alternate sites (another business unit or internal platform team), use an internal service agreement or documented operational commitment. CP-6 is explicit about “necessary agreements.” Treat that as required evidence, not optional process. ¹

Step 4: Implement technical controls to ensure backups actually land at the alternate site

• Configure replication/copy jobs to the alternate site.
• Enforce immutability or write-once behavior where your platform supports it (document the configuration; don’t rely on intent).
• Restrict deletion and privilege paths (separate roles for backup administration vs restore approval).
• Log backup copy job status and retention at the alternate site.

Step 5: Document retrieval and restore procedures tied to the alternate site

Your runbook should answer:

• Where the backups are (exact location identifiers).
• Who can access them (roles, groups, break-glass accounts).
• How to retrieve them if primary identity systems are impaired.
• How to verify integrity before restore (hashing/checks where feasible).
• Who approves restores and how to record decisions.

Step 6: Prove operability with recurring restore testing evidence

CP-6’s text does not explicitly say “test,” but auditors commonly expect proof that the alternate storage is more than a storage bucket with no validated restore path. Build recurring restore tests into your contingency planning program and retain the outputs as evidence.

Practical tip: Do at least one test that uses the alternate storage site as the source of truth, not the primary backup repository.

Required evidence and artifacts to retain

Keep evidence at two levels: design (what you built) and operation (what happened).

Design / governance artifacts

• CP-6 control narrative (how your alternate storage site works per system).
• Data flow or architecture diagram showing primary site and alternate storage site.
• Inventory of backup sets mapped to systems and storage locations.
• Agreements permitting storage and retrieval (MSA/SOW/SLA, order forms, internal service agreements). ¹

Operational artifacts

• Configuration screenshots or exports: replication settings, destination identifiers, retention policies.
• Access control evidence: IAM policies, group membership, break-glass procedure approvals.
• Backup job logs and monitoring reports showing successful writes to alternate site.
• Restore test records: ticket, runbook followed, logs, outcomes, lessons learned, remediation actions.

If you use Daydream to manage control operations, map CP-6 to a named owner, a written procedure, and a recurring evidence checklist so the artifacts are produced on schedule and packaged for assessors without scrambling.

Common exam/audit questions and hangups

Expect assessors to probe these areas:

• “Show me the alternate storage site.” They will ask for the exact location and evidence that backups exist there.
• “Is it a different failure domain?” Same building, same hypervisor cluster, same cloud account, or same region often triggers follow-ups.
• “What agreement guarantees retrieval?” They will ask for contract excerpts or internal commitments that permit access during an incident. ¹
• “Who can retrieve backups if SSO is down?” If identity is centralized and brittle, your retrieval plan may be non-credible.
• “Prove you can restore.” They will ask for restore test evidence, including failures and remediation.

Frequent implementation mistakes and how to avoid them

1. Co-locating backups with the primary environment

   • Fix: require a distinct site/region/account/tenancy, and document the separation rationale.

2. Assuming the cloud provider contract automatically covers emergency retrieval

   • Fix: confirm export/retrieval rights and support expectations in the agreement set; store the relevant contract pages as evidence. ¹

3. No clear retrieval path during an incident

   • Fix: write a “no-SSO” retrieval procedure with break-glass credentials stored securely, plus an approval workflow.

4. Treating backup copy success as restore readiness

   • Fix: run restores sourced from the alternate site and retain logs, tickets, and post-test writeups.

5. Evidence scattered across teams

   • Fix: centralize CP-6 evidence collection in your GRC system. Daydream is a practical fit when you need recurring evidence requests, ownership, and audit packets tied to CP-6.

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for CP-6, so you should frame risk in operational terms rather than penalties.

Operational risk if CP-6 is weak:

• A disaster or cyber event turns into prolonged downtime because backups are inaccessible, corrupted, or contractually blocked.
• Ransomware recovery fails because backups share the same compromise path or deletion privileges.
• During an audit, CP-6 gaps often cascade into broader findings across contingency planning and third-party risk because the alternate site is usually owned or operated by a third party.

A practical 30/60/90-day execution plan

First 30 days (stabilize scope and prove design)

• Name the CP-6 owner and back-up owner; document RACI.
• Create a system-to-backup mapping and identify where backups are stored today.
• Select the alternate storage pattern for each critical system.
• Pull and review third-party agreements for retrieval rights; open legal/procurement actions for missing language. ¹

By 60 days (make it real and auditable)

• Implement replication/copy to the alternate site for in-scope backups.
• Implement access controls and break-glass retrieval steps.
• Publish the retrieval/restore runbook and train the on-call team.
• Start collecting recurring evidence (job success logs, retention proofs, access reviews).

By 90 days (prove operability and close audit gaps)

• Run a restore test from the alternate storage site; document results and remediation.
• Validate contractual artifacts are stored in the control evidence repository.
• Conduct an internal control review: spot-check a sample of systems end-to-end (backup created → copied to alternate site → retrieved → restored).
• In Daydream, schedule evidence tasks so CP-6 stays continuously audit-ready.

Frequently Asked Questions

Does CP-6 require an offsite physical facility?

No. CP-6 requires an “alternate storage site,” which can be cloud-based or third-party hosted, as long as it is separate from the primary site’s failure domain and you can store and retrieve backups under defined agreements. ¹

What counts as a “necessary agreement”?

Any binding document that grants the right to store and retrieve backups from the alternate site, including contracts with third parties or an internal service agreement. The key is that retrieval permissions are explicit and defensible in an audit. ¹

If we replicate backups to another region in the same cloud account, is that enough?

Sometimes, but assessors often question whether a single account is a single failure domain due to compromised credentials or deletion privileges. If you stay in one account, document compensating controls (strong separation of duties, deletion protections) and show tested retrieval paths.

How do we evidence CP-6 without exposing sensitive details to auditors?

Provide redacted architecture diagrams, destination identifiers masked where needed, and screenshots/log excerpts that show the alternate site configuration and successful writes. Keep full sensitive details available for secure review if required.

Who should own CP-6: Security, IT, or Disaster Recovery?

Assign ownership to the team that controls backup storage and restore operations (often Infrastructure/IT Ops), with Security/GRC accountable for requirements mapping and evidence quality. Split “build” and “assure” responsibilities to avoid evidence gaps.

What’s the minimum restore testing evidence auditors accept?

A dated record showing a restore sourced from the alternate storage site, the steps followed (runbook or ticket), logs or screenshots proving success or failure, and documented remediation actions when issues are found.

Footnotes

1. NIST SP 800-53 Rev. 5 OSCAL JSON

2. NIST SP 800-53 Rev. 5; Source: NIST SP 800-53 Rev. 5 OSCAL JSON