# Disaster Recovery The following are the resiliency, HA, and DR features offered by Oracle Cloud Infrastructure. * Multiple active-active nodes at each application tier, thereby ensuring server redundancy * Redundancy strategy for database tier * Backup strategy for non-database tiers * Backup requirements for database tier * DR within a single region across availability domains: * Active-active and active-passive components * Regional subnets * Load-balancing * Storage synchronization * Database DR * DR across multiple regions: * Application replication between regions * Storage replication between regions * Cross-region copy to asynchronously copy object storage datasets * Cross-region backup copy for block volumes * Database protection between regions Sentinel SAAS can be deployed on OCI in a single availability domain, across multiple availability domains, or in multiple regions. * **Single availability domain:** Use this architecture to ensure high availability by setting up multiple application instances. Use this architecture when you want to ensure that your application is available even when an application instance goes down. The other available application instances in the availability domain continue to process the requests. * **Multiple availability domains:** Use this architecture to ensure that Sentinel is available even when one availability domain goes down. You can still access the application instances in another availability domain. * **Multiple regions:** Use this architecture to set up a disaster recovery site for Sentinel in a different region. This architecture is essentially the same as the multiple availability domain architecture, but instead of creating resources in a second availability domain in the same region, you create resources in another region. ### Disaster Recovery Architecture The following diagram is an example of Sentinel installation on OCI. The primary environment is deployed to Availability Domain 1 in Region 1, a secondary site for high availability is deployed to Availability Domain 2 in Region 1 and a disaster recovery environment is deployed in Availability Domain 1 in Region 2. The primary environment and secondary environment as well as the disaster recovery environment are all active-passive – meaning only the primary site is active for online users and transactions. ![](/files/l1ilA2FicF8CuTFuifnx) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://help.sentinelsoftware.com/sentinel-help-center/resources/policies/disaster-recovery.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.