It is always recommended to do DR planning at solution level which means that all the components making the solution should be well co-ordinated during DR. But to reach the solution level, it is important that DR design of individual components is ready.
This post documents a reference design of an important component of any solution which is Data/State store. This component is accessed by application tiers. This post is not about High Availability – Load Balancing combination. But, deals with DR scenarios where the secondary/DR site is in hot/warm/cold state.
Below diagram states the reference design of how the DR architecture commonly looks like. DR Agents play a critical role of when to call it a DR and based on that the app configuration changes to connect to available instance of Data Store.
So what are the considerations when designing the DR solution for Data Store ? Here are few important ones:
- How application will store connection string to data store and how it will get updated at the time of DR.
- How the DR site will be provisioned ?
- What will be the state of DR site at normal times – hot/warm/cold. This will depend on RTO/RPO objectives and will also determine the provisioning method.
- How the replication of data will happen between primary and DR site.
- How the failover will happen from primary to DR site ?
- How the failback will happen from DR to primary site ?
1 comment:
Thank you. Cloud Disaster Recovery is really a nice concept - it is awesome, and I appreciate your helping to share about this.
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