Nowadays, the rapid popularization of virtualization technology on x86 servers has triggered an upsurge of virtualization technology, but virtualization technology was originally only applied to large computers. Virtual partition technology on mainframe can be traced back to the sixties and seventies. As early as 1960s, IBM invented an operating system virtual machine technology, which allowed users to run multiple operating systems on a single host, allowing users to make full use of expensive mainframe resources as much as possible.
IBM 7044 computer is the first computer to use virtualization technology. Following IBM, the System/360 mainframe model 67 was also developed in the 1960s. Model 67 host virtualizes all hardware interfaces through virtual machine monitor. 1965 IBM's "M44/44X" computer project defines the management mechanism of virtual memory, and user programs can run in virtual memory. For users, these virtual memories are like "virtual machines", providing an independent computing environment for programs of multiple users.
The virtual machine technology proposed by IBM makes many new products emerge, such as IBM360/40, IBM360/67 and VM/370. At that time, these machines all had virtual machine functions. Through a technology called VMM (Virtual Machine Monitor), many virtual machine instances that can run independent operating system software were generated on physical hardware.
Because of the advantages of virtualization technology in commercial applications, RISC servers and minicomputers have become the second generation beneficiaries of virtualization technology. 1999, IBM put forward "logical partition (LPAR)" technology and a new high-availability cluster solution on AS/400. AS/400 LPAR running on POWER hypervisor makes a single server work like 12 independent servers. In 2002, IBM went further, and its AIX5L v5.2 also included the dynamic logical partition (DLPAR) implemented by IBM for the first time. DLPAR allows system resources, including processors, memory and other components, to be allocated to independent partitions without restarting the system. This ability to allocate resources without interruption not only makes system management easier, but also helps to reduce the total cost of ownership because of better utilization of resources.
However, although HP and Sun follow IBM to provide virtualization technology on their RISC servers, virtualization technology has not been taken seriously by the public, because there are still a few users who actually use mainframes and minicomputers, and the products and technologies are incompatible. Now, the development of virtualization technology has greatly benefited x86 architecture.
Previously, the virtualization technology on x86 architecture made slow progress, mainly because x86 architecture itself was not suitable for virtualization. However, this obstacle has been modified by Intel and AMD, and the instruction set of x86 processor has been solved. Another reason is the insufficient performance of x86 processors, which has been solved because the performance of x86 processors has improved rapidly. Due to the widespread popularity of x86 architecture, virtualization technology on x86 architecture has also received more attention.
With the realization of virtualization technology on x86 platform, the broad prospect of virtualization application is presented for the first time, because x86 platform can provide cheap, high-performance and highly reliable servers. More importantly, some users have begun to configure the virtualized production environment, and they need to obtain new management tools in order to gain more benefits with the development of virtualization technology.
However, compared with the virtualization technology on UNIX servers and mainframes with many years of history, virtualization on x86 servers is still in the early stage-according to Intel's blueprint, integrating hardware-assisted virtualization instructions on processors is only the first step on IA platform, and the second step is to virtualize I/O until the whole IA platform is finally virtualized. In other words, on the current x86 platform, virtualization can only be realized at the processor level, and I/O virtualization needs further development. Moreover, the virtualization technology on x86 architecture can not perfectly realize the dynamic migration between virtual partitions, which is no longer a problem on UNIX platforms and mainframes. At present, the highest planning of virtualization technology on x86 architecture is to support 8-way SMP system, which can realize the configuration of a single CPU resource.
Since 2006, from AMD and Intel on the processor level to Microsoft on the operating system level, from the emergence of a large number of third-party software vendors to the high-profile of server system vendors, we have seen a complete industrial ecosystem of server virtualization gradually taking shape. This also makes virtualization a hot topic in recent one or two years. Generally speaking, with the rapid development of new computer technology, the prospect of virtualization has almost completely changed compared with a year ago, and the prospect of the new virtualization platform is very optimistic.