Intel's
Nehalem microarchitecture—now officially known as the Intel Xeon 5500
series—offers advances in addressable memory, simultaneous multithreading and
I/O handling, providing IT managers with the ability to put even more virtual
machines on a single physical system. But as memory capacity and compute power
increase and I/O overhead diminishes, what's the new VM limit on a single
system? The answer may be the amount of risk your organization can tolerate in
terms of putting a large number of virtual eggs in one physical basket.
To reduce risk, IT managers should place a premium on moving VMs to healthy
physical systems and on data center management tools that monitor both the
virtual and physical resources in the data center.
Several years ago, Intel introduced processor technology called
FlexMigration that eases virtual-to-virtual machine movement across Intel
processors of different generations. Combined with VMware’s Extended VMotion—which
overcomes limitations in the older, strict VMotion that required exactly
matched physical processors—IT managers will have more options when it comes to
migrating VMs. The trade-off is that VMs will be presented with a processor of
the lowest-common-denominator feature set in the VMotion pool of physical
systems.
IT managers who build on virtualization platforms that provide this kind of
migration flexibility can reduce risk by ensuring that their VMs have someplace
to run in case of unplanned downtime. Managers who want to demonstrate even
greater foresight will take this a step further by ensuring that all the VM
bolt holes have sufficient memory, bandwidth, compute and storage resources to
support the business applications running on the VMs.
Reducing the risk of VM downtime also requires careful capacity planning to
keep costs in line. This is where data center management tools come into play.
IT managers must implement tools that take physical and virtual machines
into account when tracking CPU, memory, storage and network bandwidth. An
accurate reporting of these resources is even more important for regulated
enterprises or for organizations that implement tight security policies, where
machine separation and stringent access management is a requirement.
To reduce VM downtime risk while controlling costs, I recommend that IT
managers immediately implement data center management tools that provide some
kind of trend reporting. Even if these trends provide only historic data with
no prediction, this can be very useful information for understanding what is a
normal workload for your data center. This provides a good basis for making
equipment purchases and hypervisor and operating system licensing
recommendations to business managers.
Virtualization Technology News & Reviews 
