6.1

Test Networks and Datacenter Networks
When you test a recovery plan, Site Recovery Manager 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 test network settings while creating a
recovery plan. A test network does not span hosts. You must configure a test network for every network
that a recovery plan uses during recovery.
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.
A datacenter network is a network that typically supports existing virtual machines at the recovery site. You
can select a datacenter network for use as a test network. 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.
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, Site Recovery Manager synchronizes the virtual machine data on the recovery
site with the virtual machines on the protected site. Site Recovery Manager attempts to gracefully shut down
the protected machines and performs a final synchronization to prevent data loss, then powers on the
virtual machines on the recovery site. 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, Site Recovery Manager first attempts a storage synchronization. If it succeeds,
Site Recovery Manager uses the synchronized storage state to recover virtual machines on the recovery site
to their most recent available state, according to the recovery point objective (RPO) that you set when you
configure your replication technology. When you run a recovery plan to perform a disaster recovery,
Site Recovery Manager attempts to shut down the virtual machines on the protected site. If
Site Recovery Manager cannot shut down the virtual machines, Site Recovery Manager still starts the copies
at the recovery site. In case the protected site comes back online after disaster recovery, the recovery plan
goes into an inconsistent state where production virtual machines are running on both sites, known as a
split-brain scenario. Site Recovery Manager detects this state and allows you to run the plan once more to
power off the virtual machines on the protected site. Then the recovery plan goes back to consistent state
and you can run reprotect.
If Site Recovery Manager 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, Site Recovery Manager 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, Site Recovery Manager can gracefully shut down the
protected virtual machines on that datastore.
Chapter 6 Creating, Testing, and Running Site Recovery Manager Recovery Plans
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