# How to Keep Data Safe During a Site Failover > A method for keeping data backups synchronized and accessible even when a primary data center goes offline and systems must switch to a backup location. - **Patent:** US 9672117 - **Original title:** Method and system for star replication using multiple replication technologies - **Owner:** EMC IP Holding Co LLC - **Granted:** 2017 - **Status:** Active - **Times cited:** 21 - **Field:** software, telecommunications, consumer_electronics ## What it does This patent describes a way to manage data recovery when a primary production site fails. It uses a star-like topology where data is replicated to a secondary site and backed up to a separate storage location. When a failover occurs, the system reverses the flow of data, treating the replication site as the new production site. It uses a delta marker stream to track differences between storage locations, ensuring that the backup site remains consistent with the new production state even during complex recovery operations. ## What it does NOT cover - Does not cover simple data mirroring without a failover mechanism. - Does not cover data backup methods that lack a delta marker stream for tracking changes. - Does not cover cloud-native object storage replication that does not involve a site-based failover. - Does not cover hardware-agnostic data recovery that ignores the state of the production site storage. ## The clever bit The system uses a unified delta marker stream to manage differences across multiple storage tiers during a failover, effectively 'reversing' the replication logic to maintain data integrity without manual intervention. ## Real-world examples 1. Dell EMC RecoverPoint 2. Enterprise disaster recovery storage clusters 3. Multi-site data center synchronization systems ## Why it matters In enterprise IT, maintaining business continuity is critical. This patent provides a specific orchestration logic for EMC's (now Dell Technologies) data protection ecosystem, ensuring that when a disaster occurs, the backup chain does not break. It is a foundational piece of logic for high-availability storage arrays used by large corporations to prevent data loss during site outages. ## Frequently asked questions ### What does How to Keep Data Safe During a Site Failover cover? A method for keeping data backups synchronized and accessible even when a primary data center goes offline and systems must switch to a backup location. ### Who owns patent US 9672117? EMC IP Holding Co LLC owns this patent, granted in 2017. ### When does this patent expire? This patent is expected to expire on June 6, 2037, when the invention enters the public domain. ### What is patent US 9672117 cited by? This patent has been cited by 21 later patents that build on its ideas. ### What problem does this patent solve? In enterprise IT, maintaining business continuity is critical. This patent provides a specific orchestration logic for EMC's (now Dell Technologies) data protection ecosystem, ensuring that when a disaster occurs, the backup chain does not break. It is a foundational piece of logic for high-availability storage arrays used by large corporations to prevent data loss during site outages. ### What does this patent NOT cover? Does not cover simple data mirroring without a failover mechanism. **Full plain-English explainer:** https://patentbrief.org/patent/us/9672117/aws-codedeploy **Original patent:** https://patents.google.com/patent/US9672117 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How to Keep Backup Data in the Correct Order](https://patentbrief.org/patent/us/9811430/aws-codepipeline) — A method for ensuring that backup data arrives at a secondary storage location in the exact same sequence it was created at the primary location to prevent data corruption. - [How IBM's Storage Controllers Keep Data Backups in the Right Order](https://patentbrief.org/patent/us/5682513/cache-queue-entry-linking-for-dasd-record-updates) — A method for storage controllers to track and sequence data updates in a specific order, ensuring that remote backups remain consistent with the original data during a system failure. - [How Computers Safely Resume Interrupted Data Backups](https://patentbrief.org/patent/us/8307004/amazon-dynamodb) — A method for computers to pause a large data backup and resume exactly where they left off without restarting the entire process from scratch. - [How Cloud Services Automatically Switch Providers When One Fails](https://patentbrief.org/patent/us/10140638/airbnb-review-system) — A system that uses conversational AI to understand your reliability needs and automatically switches your cloud service to a backup provider if your current one goes down. - [How to Send Data Streams Independently Without Connection Overload](https://patentbrief.org/patent/us/7904576/reliable-datagram-via-independent-source-destination-resources) — A method for sending multiple streams of data between devices using independent, reliable paths that keep data in the correct order without needing a constant connection.