Disaster Recovery

DR refers to having business continuity in the event of a natural disaster or hacking that terminates an entire Azure region.

There are two ways to implement DR: standard geo-replication and active geo-replication.

Standard Geo-Replication

Standard geo-replication asynchronously replicates committed transactions from an online primary to an offline secondary in a predefined Azure region:

Figure 8.7: Figure 8.7: Standard geo-replication

In standard geo-replication:

Only one secondary is allowed in a DR paired region.

Each region has a DR pair that can only host the secondary database. The secondary database is offline and is unreadable. However, it is visible in the master database. The secondary database is readable when failover is done.

Note

The entire list of DR paired regions can be found here: https://docs.microsoft.com/en-us/azure/best-practices-availability-paired-regions.

• The secondary database is priced at discounted rates as it's unreadable.
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