Mechanisms for Cloud DR

While cloud computing platforms already contain many
useful features for supporting disaster recovery, there are
additional requirements they must meet before they can
provide DR as a cloud service.
Network Reconfiguration: For a cloud DR service to
provide true business continuity, it must facilitate reconfiguring
the network setup for an application after it is
brought online in the backup site. We have previously
proposed how a cloud infrastructure can be combined
with virtual private networks (VPNs) to support this kind
of rapid reconfiguration for applications that only communicate
within a private business environment [10].
Public Internet facing applications would require additional
forms of network reconfiguration through either
modifying DNS or updating routes to redirect traffic to
the failover site. To support any of these features, cloud
platforms need greater coordination with network service
providers.
Security & Isolation: The public nature of cloud
computing platforms remains a concern for some businesses.
In order for an enterprise to be willing to fail over
from its private data center to a cloud during a disaster it
will require strong guarantees about the privacy of storage,
network, and the virtual machine resources it uses.
Likewise, clouds must guarantee that the performance of
applications running in the cloud will not be impacted by
disasters affecting other businesses.
VM Migration & Cloning: Current cloud computing
platforms do not support VM migration in or out
of the cloud. VM migration or cloning would simplify
the failback procedure for moving an application back
to its original site after a disaster has been dealt with.
This would also be a useful mechanism for facilitating
planned maintenance downtime. The Remus system [4]
has demonstrated how a continuous form of VM migration
can be used to synchronize both memory and disk
state of a virtual machine to a backup server. This could
potentially allow for full system DR mechanisms that allow
completely transparent failover during a disaster. To
support this, clouds must expose additional hyperviso
rlevel functionality to their customers, and migration techniques
must be optimized for WAN environments