5.5

Test Networks and Datacenter Networks
When you test a recovery plan, SRM can create a test network that it uses to connect recovered virtual
machines. Creating a test network allows the test to run without potentially disrupting virtual machines in
the production environment.
The test network is managed by its own virtual switch, and in most cases recovered virtual machines can
use the network without having to change network properties such as IP address, gateway, and so on. You
use the test network by selecting Auto when you configure the network settings when you run a test.
A datacenter network is a network that typically supports existing virtual machines at the recovery site. To
use it, recovered virtual machines must conform to its network address availability rules. These virtual
machines must use a network address that the network's switch can serve and route, must use the correct
gateway and DNS host, and so on. Recovered virtual machines that use DHCP can connect to this network
without additional customization. Other virtual machines require IP customization and additional recovery
plan steps to apply the customization.
You must recover any virtual machines that must interact with each other to the same test network. For
example, if a Web server accesses information on a database, those Web server and database virtual
machines should recover together to the same network.
Performing a Planned Migration or Disaster Recovery By Running a
Recovery Plan
You can run a recovery plan under planned circumstances to migrate virtual machines from the protected
site to the recovery site. You can also run a recovery plan under unplanned circumstances if the protected
site suffers an unforeseen event that might result in data loss.
During a planned migration, SRM synchronizes the virtual machines on the recovery site with the virtual
machines on the protected site, then stops replication. SRM attempts to replicate all virtual machines and
gracefully shut down the protected machines. If errors occur during a planned migration, the plan stops so
that you can resolve the errors and rerun the plan. You can reprotect the virtual machines after the recovery.
During disaster recoveries, SRM restores virtual machines on the recovery site to their most recent available
state, according to the recovery point objective (RPO). When you run a recovery plan to perform a disaster
recovery, SRM attempts to shut down the virtual machines on the protected site. If SRM cannot shut down
the virtual machines, SRM still starts the copies at the recovery site, and automatic reprotect might not be
possible.
If SRM detects that a datastore on the protected site is in the all paths down (APD) state and is preventing a
virtual machine from shutting down, SRM waits for a period before attempting to shut down the virtual
machine again. The APD state is usually transient, so by waiting for a datastore in the APD state to come
back online, SRM can gracefully shut down the protected virtual machines on that datastore.
SRM uses VMware Tools heartbeat to discover when a virtual machine is running on the recovery site. In
this way, SRM can ensure that all virtual machines are running on the recovery site. For this reason, install
VMware Tools on protected virtual machines. If you do not or cannot install VMware Tools on the protected
virtual machines, you must configure SRM not to wait for VMware Tools to start in the recovered virtual
machines and to skip the guest operating system shutdown step. See “Change Recovery Settings,” on
page 85.
After SRM completes the final replication, SRM makes changes at both sites that require significant time and
effort to reverse. Because of this time and effort, you must assign the privilege to test a recovery plan and
the privilege to run a recovery plan separately.
Chapter 4 Creating, Testing, and Running Recovery Plans
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