2 

3 

Planned Failover & Fallback

Planned Failover can be used when a site must go down for local maintenance or a limited period of time. Planned Failover minimizes service interruption time during site migration or full site maintenance.

For Asynchronous pairs, the unique feature of a planned failover is its ability to continue to keep a journal of data changes, eliminating the need for an initial data resynchronization after planned fallback. A planned failover should only be for a limited period of time.

Note: Since the journal volume is not being replicated to the remote site, it can be fully utilized quickly depending on volume activity. Therefore, attention should be paid to the journal volume to make sure that it is not reaching its load threshold. A journal volume can be resized if necessary Upon reaching the journal load threshold, an alarm will be triggered notifying the administrator to consider a journal resizing.

 

Planned Failover Wizard

Notes:  Before starting the wizard, close open applications to prevent further write operations to exposed volumes.  Make sure to flush the File System and Application cache at the local site (as an example this can be done by closing the iSCSI initiator session).

 

To open the Planned Failover wizard:

1.	Select the site to failover.

2.	Right click and select Planned Failover…

Figure ‎3-1. Planned Failover

3.	The Planned Failover wizard opens.

4.	Click Next.

Figure ‎3-2. Planned Failover Wizard

Failover Pairs

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

2.	Click Next.

Figure ‎3-3. Failover Pair(s) Selection

Access Rights

Define access rights for host following the volume(s) failover to the secondary site. The default ACL is R/W, enabling full access privileges to the failover volumes on the secondary site.

1.	Click Next.

Figure ‎3-4. Access Control Privileges

2.	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 parameters. When finished, click Next. For more information, refer to the Nexsan iSeries Manager User Manual.

Figure ‎3-5. Access Control Configuration

3.	Click Next.

Figure ‎3-6. Failover Summary

Start Failover

	Click Finish to begin failover.

Figure ‎3-7. Failover Started

 

Figure ‎3-8. Failover Completed

Fallback Wizard

After a planned failover, use the Fallback wizard to fallback volumes from the remote site to the local site.

To open the Fallback Wizard:

1.	Select the remote site.

2.	Right click and select Fallback…

Figure ‎3-9. Fallback

3.	The Fallback wizard opens.

4.	Click Next.

Figure ‎3-10. Fallback Wizard

Fallback Pairs

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

2.	Click Next.

Figure ‎3-11. Fallback Pair(s) Selection

Access Rights

Define access rights for the associated hosts after the volume(s) fallback to the secondary site. The default ACL is R/W, enabling full access privileges to the failover volumes on the secondary site.

1.	Click Next.

Figure ‎3-12. Access Control Privileges

2.	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 ‎3-13. Access Control Configuration – Part I

3.	Click Next.

Figure ‎3-14. Access Control Configuration – Part II

Start Fallback

	Click Finish to begin fallback.

Figure ‎3-15. Fallback Summary

Figure ‎3-16. Fallback Started

Figure ‎3-17. Fallback Completed