Sitecore Experience Manager

The HADR hot-warm process

Abstract

Learn about the process involved in recovering your data with HADR hot-warm.

Sitecore Managed Cloud uses the Sitecore Disaster Recovery service to offer the following three options to maintain a high availability disaster recovery (HADR) service:

Unlike HADR Basic, the hot-warm option includes a secondary data center that always has a fully furnished Sitecore environment set up. This setup ensures that all the Azure resources match the sizes/instance counts in your primary data center. As a result, the hot-warm recovery option has a shorter recovery time objective (RTO), than the HADR basic option because everything is already prepared.

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If you are using the HADR hot-warm option, in the event of an outage the Sitecore Managed Cloud disaster recovery service sets the following process into action:

  1. Deploy a new Sitecore environment in the secondary data center and shut down your web applications.

  2. Use active geo-replication to sync the data between the primary and secondary Azure SQL.

  3. Sync the sizes/tiers of all your Azure resources.

  4. Sync the file contents of all of your web applications.

  5. Set up an outage page to ensure your customers are aware that your site is temporarily down.

  6. Set up a traffic manager to switch between the primary Content Delivery (CD) server and the outage page.

  7. Set up email alerts to notify the Managed Cloud Operations team whenever an availability test fails.

When a disaster occurs, Sitecore immediately requests confirmation from you to run the full recovery process. After you confirm, Sitecore triggers the following recovery process:

  1. Start your web applications in the secondary data center.

  2. Re-index all of your website content and xDB indexes.

  3. Switch the traffic manager to the secondary Sitecore instance.

After Sitecore has enacted the failover process, and the cause of the disaster has been fixed, you and the Managed Cloud Operations team will agree on a time to return to the primary data center.

At this point, the data in the primary data center is stale, therefore Sitecore repeats the failover steps to export the secondary instance into the primary data center and update the data in the primary instance.