One of the issues that is holding back further adoption of virtualization are concerns about the performance capabilities of virtualized servers. For this reason the vast majority of the servers that are running virtual machine software tend to be, for example, file server applications rather than I/O sensitive database servers.
This performance issue raises its ugly head further still as you start to load more virtual machines on each physical server. As each virtual server environment begins to make I/O calls the performance of the overall system drops because the each virtual server environment is fighting for bandwidth.
To alleviate this problem companies such as Xsigo Systems have come up with appliances that better manage the distribution of I/O calls made to various storage resources on the network. But the people who make the actual Ethernet adapters that connect storage devices to systems are arguing that offering such as Xsigo represent a short term solution to a bigger problem.
Companies such as Neterion, which makes 10 gigabit Ethernet cards that are sold by companies such as IBM, Hewlett-Packard, EMC, Sun Hitachi and Fujitsu, argue that the next generation of Ethernet adapters will support both single-root and multi-root virtualization. A single-root implementation allows multiple virtual environments to share an Ethernet adapter, while a multi-root implementation will allow multiple virtual server environments running on multiple physical servers to share the I/O processing power of the same Ethernet adapter.
In anticipation of these capabilities Neterion has added support for dynamic provisioning and load balancing on adapters that will lever quad-core processors to create up to 16 I/O channels on single adapter with a 17th channel used to mange the overall process using a set of policies that can be set by the IT department to give I/O priority to certain types of applications and data.
What all this means is that while virtualization is very much in vogue today, there is a second wave of virtualization in the offing for 2009 that is going to tackle performance sensitive applications that typically run on very expensive database servers. The upside of these efforts is that there is a lot of money to be potentially saved in consolidating database servers but in order to accomplish that task IT organizations will probably have to invest in a new generation of high performance multicore systems sporting 10 Gigabit Ethernet adapters. No doubt these machines will be a little trickier to manage than their predecessors given all the complexities associated with I/O in these environments, but as is true with all things in IT these days you have to spend a little money to save a lot of money.