The advantages of server virtualization can be so tempting, it’s easy to overlook a number of limitations to this method. Before attempting to design a solution that should get acquainted with the peculiarities of the methods of server virtualization, as well as the architecture and the needs of its own network administrator.
Servers, designed for applications with high demands on computing power, virtualization is contraindicated. The reason is that virtualization actually divides the processing power of servers to virtual servers. If the computing power of the server is not enough for normal functioning of the application, all processes are slowed down. Then the problem where its performance under different circumstances did not require much time, can now run for hours. Perhaps even worse: when the server does not satisfy the requirements put forward by the processing of information, there is a risk of system failure. Before dividing a physical server into multiple virtual machines, network administrators should pay particular attention to the level of processing power CPU.
It would also be unwise to overload the server’s CPU, creating an excessively large number of virtual servers on one machine. The more virtual machines must maintain a physical server, the less processing power will get to each virtual server. Also, keep in mind that the physical servers have limited disk space. Too many virtual servers could adversely affect the ability of servers to maintain the required amount of data.
Another limitation is the migration. Nowadays, possible migration of virtual servers on one physical machine to another only can be done only if both physical machines are used by the processor of the same manufacturer. If your network uses a server on an Intel processor and another that uses a AMD processor, it is impossible to translate the virtual server from one machine to another.
Why would be the administrator primarily interested in the migration of a virtual server? In situations where a physical server needs service, the translation of virtual servers on other machines can reduce the downtime of the application. If migration is not possible, all applications running on virtual servers that are placed on a given physical machine will be unavailable during the lifetime of the maintenance procedures.
Many companies have invested in virtualization, in spite of its limitations. With the progression of server virtualization technology the need for large data centers will decrease. Also with reduced power consumption and heat dissipation, making use of virtual servers is attractive, not only financially but also in terms of environmental protection. If the network servers were used at a level close to their potential, we would expect the appearance of larger, more efficient computer networks. Without exaggeration, one can argue with virtual servers that can cause an entire revolution in the computer industry. We can only wait and monitor the development of this process.