Oracle's disaster recovery licensing rules are among the most misunderstood in the entire Oracle portfolio and the most expensive to get wrong. The difference between a truly passive standby (free under the 10-day rule) and an active standby (requiring full processor licensing on both primary and DR) can be $500K to $3M+ in a single environment. A single read-only query on a Data Guard physical standby transforms it from a free disaster recovery asset into a fully licensable Active Data Guard deployment.
This guide is part of our Oracle database options coverage. See also: Active Data Guard Licensing | Diagnostics Pack | Tuning Pack | Advanced Security | SE2 Licensing Guide | Oracle Database Licensing Guide
Oracle recognises five distinct disaster recovery configurations, each with fundamentally different licensing implications. The licensing requirement is determined by the activity level of the standby, not its label, not its intent, and not how rarely it is used.
| DR Type | How It Works | Activity Level | Licence Required? | Cost (16-core EE) |
|---|---|---|---|---|
| Cold standby | Server powered off or Oracle not running. Activated only during failover. | None | No. Covered by 10-day rule. | $0 |
| Physical standby (Data Guard) | Database mounted, receiving and applying redo logs. Not open for queries. | Passive (redo apply only) | No. Covered by 10-day rule (if truly passive). | $0 |
| Warm standby | Database periodically opened for read access, maintenance, health checks. | Active (intermittent) | Yes. Full licensing required. | $380,000 |
| Logical standby (Data Guard) | Database open for read/write. SQL Apply converts redo into SQL. Queryable. | Active (continuously open) | Yes. Full licensing required. | $380,000+ |
| Snapshot standby | Physical standby temporarily converted to read-write for testing. Reverts after. | Active (during snapshot period) | Yes. Licensed while in snapshot mode. | $380,000 |
Oracle defines "passive" extremely narrowly: the database must be in mount mode applying redo logs only. No user connections. No application access. No read-only queries. No reporting. No OEM monitoring that triggers Diagnostics Pack usage. A single SELECT statement executed by a DBA checking data consistency transforms the standby from free (10-day rule) to fully licensable. On a 2-socket, 16-core server, that single query creates a $380,000 licensing obligation for Oracle Database EE, plus licensing for any options used on the primary.
Oracle's 10-day rule permits running Oracle software on an unlicensed standby server for up to 10 cumulative days per calendar year during genuine failover events. This is the cornerstone of free DR licensing, but its conditions are far more restrictive than most organisations realise.
| Condition | 10-Day Rule Applies? | Explanation |
|---|---|---|
| Genuine unplanned outage | Yes | Standby activated because primary has failed. Each day of activation counts toward the 10-day cumulative total. |
| DR testing / failover drill | No | Planned DR tests where both primary and standby are active do not qualify. Primary must be genuinely down. |
| Planned maintenance | No | Failover to DR while patching primary is planned use, not covered by the 10-day rule. |
| Read-only reporting on standby | No | Any reporting or query workload is productive use that requires full licensing regardless of the rule. |
| Exceeded 10 cumulative days | No (exceeded) | Once the 10-day limit is exceeded, the standby must be fully licensed for the remainder of the year. |
| Cold standby powered off | Yes | Server with Oracle installed but not running qualifies. Activation during failover starts the counter. |
| Physical standby in mount mode | Yes | Database receiving and applying redo in mount mode (not open) qualifies as passive. |
The 10-day allowance accumulates across the entire calendar year. If your primary fails for 3 days in March and 4 days in September, you have used 7 of your 10 days. A third outage lasting more than 3 days would exceed the limit. Track every activation day in a formal log with timestamps, incident tickets, and proof that the primary was genuinely down. This log is your primary defence in an audit. Without it, Oracle can assert that any standby activation exceeded the 10-day limit.
Oracle Data Guard is included with Oracle Database Enterprise Edition at no additional licence cost. The Data Guard software itself requires no separate licence. However, the standby database that Data Guard creates and maintains does require licensing if it performs any active work beyond passive redo application.
| Data Guard Configuration | Standby Activity | Licence Required? | Cost (16-core) |
|---|---|---|---|
| Physical standby: mount mode | Redo apply only. Not open. No user connections. | No (10-day rule) | $0. The only truly free DR configuration. |
| Physical standby: read-only open | Database opened read-only for queries (Active Data Guard feature) | Yes. ADG option + full DB EE. | $380,000 DB EE + $92,000 ADG = $472,000 |
| Logical standby | SQL Apply. Database open for read and write. Queryable. | Yes. Full DB EE licensing. | $380,000+ |
| Snapshot standby | Temporarily writable for testing. Reverts to physical standby after. | Yes. While in snapshot mode. | $380,000 during writable period |
| Switchover (planned role change) | Primary and standby swap roles. Brief transition. | No. Temporary switchover covered. | $0 during brief switchover |
| Failover (unplanned) | Standby becomes primary during outage. Original primary is down. | No (10-day rule, if within limit) | $0 within 10-day limit |
Active Data Guard (ADG) is a separately licensed Oracle Database option that enables read-only access to a physical standby while it continues to apply redo from the primary. ADG costs $11,500 per processor at list price and must be licensed on both the primary and the standby server, with the standby also requiring full Oracle Database Enterprise Edition licensing.
| ADG Feature | Triggers ADG Licensing? | How It Creates Exposure |
|---|---|---|
| Real-Time Query (read-only standby) | Yes | Opening the standby read-only while redo apply continues. Any SELECT on an open standby = ADG licensing. |
| Automatic Block Repair | Yes | Repairs corrupted blocks by fetching from standby. Enabled automatically in some configurations. |
| Real-Time Cascade | Yes | Standby forwards redo to another standby in real-time. ADG licensing on all servers in the chain. |
| Far Sync Instance | Yes | Lightweight instance that receives and forwards redo. Requires ADG licensing even with no data. |
| DML Redirection | Yes | Write operations on ADG standby redirected to primary transparently. Requires ADG licensing. |
| Fast Incremental Backup from Standby | Yes | Offloading RMAN backups to standby. ADG-specific feature requiring licensing. |
For a complete Active Data Guard deep-dive, see our Active Data Guard Licensing guide.
| Scenario | Primary Cost | DR Cost | Total DR Exposure | Annual Support |
|---|---|---|---|---|
| Passive physical standby (mount mode, 16-core) | $380,000 (licensed) | $0 (10-day rule) | $0 | $0 additional |
| Active Data Guard standby (16-core, read-only) | $380,000 + $92,000 ADG | $380,000 + $92,000 ADG | $472,000 | $103,840/year |
| Logical standby (16-core, open for queries) | $380,000 | $380,000 | $380,000 | $83,600/year |
| Snapshot standby for quarterly testing | $380,000 | $380,000 | $380,000 | $83,600/year |
| VMware cluster DR (10-host shared cluster) | $380,000 | $3,800,000 (all 80 proc) | $3,800,000 | $836,000/year |
If your primary database uses licensed Oracle options or management packs, the standby must be licensed for the same options, even if the standby is not actively using those features. Oracle's position: the standby could use the feature during failover, so it must be licensed proactively. This applies to actively licensed standbys; it does not apply to truly passive standbys under the 10-day rule.
| Option / Pack | List Price (per proc) | DR Rule | Cost on 8-proc DR Server |
|---|---|---|---|
| Diagnostics Pack | $7,500 | Must match primary if standby is actively licensed | $60,000 |
| Tuning Pack | $5,000 | Must match primary | $40,000 |
| Partitioning | $11,500 | Must match primary | $92,000 |
| Advanced Security (TDE) | $15,000 | Must match primary. TDE encrypted data requires the option on standby. | $120,000 |
| Active Data Guard | $11,500 | Must be licensed on BOTH primary and standby | $92,000 (standby) + $92,000 (primary) |
| Advanced Compression | $11,500 | Must match primary if compressed data exists on standby | $92,000 |
| Environment | DR Licensing Rule | Practical Impact | Compliance Strategy |
|---|---|---|---|
| VMware / Hyper-V / KVM | All hosts in cluster must be licensed if DR VM could migrate. Soft partitioning not recognised. | DR VM on shared 10-host cluster = all hosts licensed = $3.8M+ | Isolate DR VM on dedicated host with affinity rules. Keep host powered off until failover. |
| Oracle VM (OVM) | Hard partitioning recognised. Licence only assigned resources. | Significantly cheaper than VMware for DR. | Use OVM for DR environments where VMware licensing would be prohibitive. |
| AWS / Azure / GCP (BYOL) | 2 vCPUs = 1 processor licence. DR instance must be licensed when running. | Stopped/deallocated instances not licensable. Running instances must be licensed. | Keep DR instances stopped until failover. Automate startup only during genuine outage. |
| Oracle Cloud (OCI) | 1 OCPU = 1 processor licence. BYOL or licence-included. | OCI Pilot Light DR patterns minimise licensing by keeping instances minimal. | Use OCI DR patterns with minimal compute until failover. Scale up only during activation. |
| Cross-cloud / hybrid DR | On-prem primary + cloud DR (or vice versa). Each environment licensed independently. | Cloud DR must be licensed under cloud BYOL rules even if primary is on-prem. | Ensure BYOL licences cover both primary and DR. Or use licence-included cloud options. |
For virtualisation best practices, see our Licensing in Virtualised Environments guide and Partitioning Policy guide. For cloud BYOL rules, see our Oracle BYOL guide.
| Audit Finding | How It Occurs | Typical Cost Impact | Prevention |
|---|---|---|---|
| Read-only queries on physical standby | DBA opens standby read-only for validation, reporting, or testing. DBA_FEATURE_USAGE_STATISTICS records ADG usage. | $380K to $500K+ (full DB EE + ADG option) | Block all user connections to standby. Disable read-only open. Restrict DBA access to mount-mode only. |
| 10-day rule exceeded | DR activated for multiple outages totalling more than 10 cumulative days. No tracking log. | $380K+ (full licensing from day 11 onward) | Maintain formal activation log. Set alerts at 7 days cumulative. |
| DR used for planned maintenance | Production moved to standby during patching. Primary still accessible. | $380K+ (planned use not covered by 10-day rule) | Implement zero-downtime patching. Never failover for planned maintenance. |
| Database options on unlicensed standby | Primary uses Diagnostics Pack, Partitioning, or TDE. Standby inherits but is not licensed. | $100K to $500K+ per standby | If standby is actively licensed, ensure all primary options are also licensed. |
| VMware DR cluster not isolated | DR VM runs on shared VMware cluster. Oracle requires licensing all hosts. | $1M to $5M+ (cluster-wide EE licensing) | Dedicate a host for Oracle DR VMs. Use affinity rules. Document isolation. |
| OEM Diagnostics Pack on standby | OEM configured to monitor standby. Diagnostics Pack features triggered automatically. | $60K to $200K+ (Diagnostics Pack on standby) | Exclude standbys from OEM monitoring or restrict to basic monitoring (CONTROL_MANAGEMENT_PACK_ACCESS = NONE). |
For comprehensive audit defence, see our Oracle Audit Response Playbook and Oracle Audit Guide.
1. Maintain strict standby passivity. Ensure all DR standbys remain in mount mode with redo apply only. Block all user connections. Disable read-only open. Do not use standby for reporting, testing, data validation, or any workload.
2. Track 10-day rule usage formally. Maintain a formal activation log documenting every day the standby is activated: date, time, duration, incident ticket, confirmation that the primary was genuinely down. Set automated alerts at 7 days cumulative.
3. Isolate DR in virtualised environments. If using VMware, dedicate a specific host for Oracle DR VMs. Configure affinity rules preventing migration. Consider keeping the DR host powered off until failover. Document isolation for audit defence.
4. Audit DBA_FEATURE_USAGE_STATISTICS on standbys. Run quarterly on all standby databases. Check for any Active Data Guard feature usage, Diagnostics Pack triggers, or other option activation. Feature usage is recorded permanently.
5. Restrict OEM monitoring on standbys. Oracle Enterprise Manager automatically enables Diagnostics Pack features when monitoring. Either exclude standby databases or configure basic monitoring only.
6. Document DR architecture and licensing rationale. Maintain a formal document describing your DR architecture, the licensing basis for each standby, and controls in place. Available within 48 hours of an Oracle audit notification.
The 10-day rule allows Oracle software to run on an unlicensed standby server for up to 10 cumulative days per calendar year during genuine unplanned failover events. The primary must be genuinely down during this period. The rule does not cover planned maintenance, testing, reporting, or any routine workload. Days are cumulative across the year, not consecutive. Once exceeded, the standby must be fully licensed.
The Data Guard feature itself is included free with Oracle Database Enterprise Edition. No separate licence is required for redo transport and apply. However, the standby database requires licensing if it performs any active work. A physical standby in mount mode (redo apply only) is free under the 10-day rule. A physical standby opened read-only requires Active Data Guard licensing ($11,500/processor) plus full DB EE licensing. The technology is free; the standby activity is not.
No, not without licensing. Any reporting workload on a standby database, whether read-only queries, BI tool connections, data extraction, or application access, constitutes productive use requiring full licensing. If the standby is opened read-only while applying redo, this triggers Active Data Guard licensing ($11,500/processor on both primary and standby) plus matching DB EE licensing. There is no "light use" or "occasional reporting" exemption.
If the standby is actively licensed (ADG standby, logical standby, or any standby requiring full licensing), then yes. All database options and packs used on the primary must also be licensed on the standby at matching quantities. If the standby is truly passive under the 10-day rule, options do not need separate licensing. However, if the 10-day rule is exceeded or the standby becomes active, options licensing is triggered retroactively.
Oracle requires licensing all physical cores across all hosts in a VMware cluster where a DR VM could potentially run. A DR standby VM on a shared 10-host cluster requires licensing every host, potentially $1M to $5M+. The solution: isolate the Oracle DR VM on a dedicated host with affinity rules, or use Oracle VM (hard partitioning). Alternatively, keep the DR host powered off until a genuine failover event.
Yes. On AWS, Azure, and GCP, stopped or deallocated instances are not considered running and do not require licensing. However, the moment you start the DR instance, licensing is required under BYOL rules (2 vCPUs = 1 processor licence). Automate DR startup to occur only during genuine failover events and track activation time against the 10-day rule if no separate licence exists.
Data Guard is included free with Oracle Database Enterprise Edition and provides redo transport, redo apply, switchover, and failover for standby databases. The standby must remain in mount mode (passive) for free licensing. Active Data Guard is a separately licensed option ($11,500/processor) that enables read-only access to the standby while it continues applying redo. ADG also provides features like Automatic Block Repair, Real-Time Cascade, Far Sync, and DML Redirection. Any feature beyond basic redo apply triggers ADG licensing.
Yes. Oracle Database Standard Edition 2 includes basic Data Guard (physical standby) for disaster recovery. The standby must remain passive (mount mode, redo apply only). Active Data Guard features (read-only standby, Automatic Block Repair) are not available for SE2 and would trigger Enterprise Edition licensing if used. SE2 also includes SE High Availability (SEHA) for cold/warm failover via Oracle Clusterware. See our SE2 Licensing Guide for details.
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