Server Virtualization Technology for Mission-critical Systems
SekiguchiAs for conventional server virtualization technology, in contrast to advantages such as the possibility of operating legacy systems and improved flexibility of systems, it is often the case that virtualization makes systems more complicated, thereby reducing their processing performance. For example, since the performance overhead becomes pretty big, the database finds it quite difficult to run in a virtual environment.
Given that state of affairs, we are focusing our efforts on development of server virtualization technology from a separate viewpoint to that previously taken. For example, input/output (I/O) processing (namely, disk access and network access) is allowed to access hardware directly from logical servers. In other words, physical devices can be "seen" from logical servers. We call this feature "hardware transparency"—one special feature of Hitachi’s server virtualization feature "Virtage".
SekiguchiIt is easy to switch OSs between physical servers and logical servers. For example, during a season when access is expected to concentrate on on-line shopping, it is possible to switch from a logical server to a physical server and speed up processing speed. In essence, a new operating style that uses physical servers and logical servers separately according to purpose and application is realized.
SekiguchiThinking of the previously mentioned example regarding setting up a development and test environment, we see that since a disk is virtualized by standard virtualization technology, if any kind of conversion operation has to be done, migration to a physical environment is difficult. With Virtage, however, it is easy to migrate a test system set up in the virtual environment of a logical server to the real environment of a physical server without any kind of conversion. In this manner, it is expected that the lifecycle of server operation will become smooth and simple. Similarly, in the case of setting up a power-saving system, under the condition that system load is decreasing, consolidating logical servers makes "agile operation"—namely, the power supply of surplus physical servers drops and electrical power consumption is reduced—possible.
Figure 2: Transparency of physical resources and logical resources
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