Cisco and VMware are working on a proof-of-concept around the idea of using VMware's VMotion technology to move live virtual machines between multiple data centers, a capability that would aid in such areas as load balancing, data center maintenance and disaster avoidance. The two companies demonstrated the proof-of-concept during the Cisco Live show. However, VMware officials warn that more work needs to be done to make the concept a reality.
Cisco Systems and VMware are developing ways that enterprises can use
VMware's VMotion technology to move live virtual machines from one data center
The two companies showed off a proof-of-concept at the Cisco Live 2009 show
in San Francisco, and demonstrated
the capabilities during Cisco CTO
Padmasree Warrior's keynote
address July 2.
The project is still in the proof-of-concept stage, but VMware official Guy
Brunsdon said in a recent blog post that moving live virtual servers to other
locations over a WAN holds promise for businesses in a number of areas.
In particular, the capability would help enterprises in load balancing
compute resources over multiple sites, Brunsdon said in his blog posted June
29. Businesses also could save power and cooling costs by being able to
dynamically consolidate VMs to fewer data centers, he said.
In addition, businesses could avoid downtime during maintenance procedures
in data centers by migrating applications offsite, and they also could more
easily avoid natural disasters by proactively migrating important application
running on VMs to another facility.
has worked well in migrating live VMs from one host to another. In
addition, VMware offers disaster recovery capabilities with its vCenter Site
Recovery Manager, which enables businesses to improve their disaster recovery
capabilities through automating recovery steps, testing recovery plans without
interrupting the VMs, and providing steps for building and managing disaster
However, there are particular challenges to the idea of moving live virtual
servers from one site to another, Brunsdon said.
"This, of course, is a non-trivial thing to do," he wrote. "There is the
challenge of moving a VM over distance (which involves some degree of
additional latency) without dropping sessions. To maintain sessions with
existing technologies means stretching the L2 domain between the sites-not
pretty from a network architecture standpoint. And then there is the storage
piece. If you move the VM, it has to remotely access its disk in the other site
until a Storage VMotion occurs."
For example, both the data center maintenance and disaster avoidance
scenarios would require a Storage VMotion to move the disk image to the other
Cisco and VMware engineers last year began working on the idea of moving VMs
over long distances between multiple data centers, Brunsdon said. The joint
Cisco-VMware lab in San Jose, Calif.,
has run several tests of disparate distances, he said. The demonstration at
Cisco Live covered a distance of about 50 miles, he said.
According to a diagram of the San Jose-to-San
Francisco test, the San Jose site
includes VMware ESX servers and Catalyst 6500 switches from Cisco. At the San
Francisco site were ESX servers and Cisco's Nexus 5000
and 7000 switches.
Linking the two sites was an 80-kilometer single-mode optical fiber.
Gordon Haff, an analyst with Illuminata, said disaster recovery is a benefit
that VMware has been touting with virtualization for several years.
A key benefit is the ability to create a disaster recovery plan that doesn't
entail spending the money to buy compute resources and having them sit idle in
case of an emergency, Haff said. Virtualization enables businesses to work with
the systems they have and use VMs for disaster recovery needs.
"You can use most resources normally most of the time," he said. "But in the
case of a problem, you can shift resources, but you don't have a lot of idle