HP StorageWorks Continuous Access EVA Administrator Guide (T3687-96043, December 2005)

For all operating systems, including VMware Virtual OSs, but excluding Windows, stop all I/O to
the virtual disks in source DR groups a nd unmount associated volumes or file systems.
For VM ware, also shut down each vir tua l machine on the VMware server, and either leave the vir tual
machines off until you fail back the LUNs, or, using the VM configuration editor, remove all LUN
assignments in the hardware configuration files.
For Windows, flush all cache files and shut down the operating system. Small files held in Windows
cache can disrupt remote replication. Reboot thehostasWindowsrequires;HPContinuousAccess
EVA is neutra l to rebooting the host.
4. Fail over the destination DR group.
In the replication manag er, select the destination DR group and then select Ac tions > Failover.See
online help for additional information.
5. To control the merging of data at the destination (previous source), suspend replication on the less
important DR groups. This forces the controllers to replicate the most important data first when the
links to the previous source are re-established. For more information, see Throttling merge I/O
after logging.
6. If you p lan to operate for an extended time a t the remote site and you need to enable failsafe
mode on a DR group, perform these steps. The n ew destinatio n (previous source) array and Fibre
Channel links must be functioning.
a. If the DR group is suspended, resume it and wait for the l o g disk to finish merging.
b. Change the DR group to failsafe mode.
NOTE:
You can enable failsafe mode at the destination array while a merge or full copy is
being performed.
7. Issue o perating system commands for resuming host I/O to the new source disks. For operating
system specifics, see Resuming I/O a fter failover.
After a failover, you have three options if the cause of the failover is resolved:
• Remain failed over on the remote array.
• Return operations to the local array (see Fail back to the original source (Revert to Home)).
• Return operations to new hardware at the local site (see Return operations to new hardware).
Unplanned failover
Possible scenario: You have experienced an unplanned loss of the local site or the source array. The
duration of the outage is unknown. The hardware components (hosts, array controllers, and switches, for
example) at the local site may or may not rem ain intact.
Action summa ry: Fail over the destination DR group. When the local site is back online, you can fail
back to the previous source array or to a replacement array. Figure 8 diagra ms an unplanned transfer of
operations to a remote site.
Procedure:
1. If local hosts are running and you ca n access them, stop all host I/O.
For all operating systems, including VMware Virtual OSs, but excluding Windows, stop all I/O to
the virtual disks in source DR groups a nd unmount associated volumes or file systems.
For VM ware, also shut down each vir tua l machine on the VMware server, and either leave the vir tual
machines off until you fail back the LUNs, or, using the VM configuration editor, remove all LUN
assignments in the hardware configuration files.
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