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Disaster Failover, Recovery & Fallback

Disaster (Unplanned) Failover refers to the case when a primary site was lost suddenly and there is no way to access it using Nexsan iSeries Manager. Disaster failover is manually implemented after a site has gone offline. Volume and pair constructions at the local site may or may not still be intact. If the volume and pair constructions at the local site have been lost during the disaster, a recover operation must be performed before the site can fallback.

Note: In order to access data in the secondary site, you must perform a Disaster Failover.

Disaster Failover Wizard

To open the Disaster Failover wizard:

1.	Open Unplanned (Disaster) Wizard from secondary (remote) site.

2.	Right click and select Disaster Failover…

Figure ‎4-1. Unplanned Failover

The Disaster Failover wizard opens.

Failover Pairs

1.	Select the consistency groups or stand-alone pairs to failover.

2.	Click Next.

Figure ‎4-2. Failover Pair(s) Selection

Access Rights

Define access rights for host after the volume(s) failover to secondary site. By defaults, everyone has full access privileges to the failover volumes on the secondary site.

	Click Next.

Figure ‎4-3. Access Control Privileges

3.	Click Next to use default values for access privileges. Or Change default access privileges for the volume that failed over to the secondary site by clicking Edit ACL… and define desired parameters. For more information, refer to the Nexsan iSeries Manager User Manual.

Figure ‎4-4. Access Control Configuration – Part I

4.	Click Next.

Figure ‎4-5. Access Control Configuration – Part II

5.	Click Next.

Figure ‎4-6. Disaster Failover Summary

Start Disaster Failover

	Click Finish to begin disaster failover.

Figure ‎4-7. Disaster Failover Started

Figure ‎4-8. Disaster Failover Completed

Recovery after a Disaster

After performing Disaster Failover, you must complete the following steps before your system will be restored.

Note: Before starting recover wizard, do the following in Nexsan iSeries Manager:  Add reconstruct site object.  Add Nexsan iSeries or Nexsan iSeries Cluster to reconstruct site object.  Configure IP and Portal for added Nexsan iSeries.  Define IP Routes.

 

1.	Use the Recover Wizard to recover your local site.

2.	Replicate (initial sync and replicate)

3.	Perform Fallback

Recover Wizard

To open the Recover wizard:

1.	Select the site to recover from.

2.	Right click and select Recover...

Figure ‎4-9. Open Recover Wizard

3.	Click Next.

Figure ‎4-10. Recover Wizard

4.	The wizard will guide you through the rest of the steps necessary to recover all of your pairs.

Note: The steps to recover are identical to creating a new pair. However, ensure that the parameters are identical to those that you want to recover from.

 

5.	After rebuilding the pair(s) a Review Summary appears.

6.	Click Apply.

Figure ‎4-11. Review Summary

7.	Click Finish.

Figure ‎4-12. Recovery Ended Successfully

Replication

After completing the Recover Wizard, you must start replication.

Note: Before starting replication, make sure that the Init Sync Type for your pairs is suitable for your network. You can change the Init Sync Type from the Pair Properties dialog box.

 

To start replication:

1.	Select the remote site.

2.	Right click and select Replicate >Start

Figure ‎4-13. Replicate Menu

Fallback

After Replication, when all the pairs are synchronized, you can perform Fallback.

To open the Fallback Wizard:

	Follow the steps described in Fallback Wizard.