Sun Microsystems 10 manual Summary of virtualization technologies

Version 3.1-enSolaris 10 Container Guide - 3.1 2. Functionality Effective: 30/11/2009

2.2.5. Summary of virtualization technologies

[ug] The virtualization technologies discussed above can be summarized in the following table – compared to installation on a separate computer.

	Separate	Domains/	Logical	Containers	Consolidation in
	computer	Physical	partitions	(Solaris zones)	one computer
		partitions		in an OS
Separation	+	O	+(Software)	+ (Software)	-
			- (Hardware)	- (Hardware)
Application	+	+	+	+	-
SW maintenance	-	-	-	+	O
HW maintenance	+	+	O	O	O
Delegation	-	-	-	+	-
Scalability	O	+	O	+	+
Overhead	-	-	-	+	+
OS versions	one each	several	several	one	one

Table 2: [ug] Summary of virtualization technologies

Key for the meaning of the symbols:

∙+ good

∙O is neither good nor bad

∙- means: has disadvantages

While separation is of course best in a stand-alone computer. Physical partitions use the same cabinet with shared power supplies (fire can harm each partition), although the partitions are independent. Lpars, LDom and containers are separated in the OS environment only.

Consolidation in an operating system reveals all that is visible in the applications to each application. In all other cases, applications are separated.

Unified SW maintenance can only be performed with zones and consolidation in one computer. The other technologies require multiple maintenance.

HW maintenance on the machine of the application is practicable only for domains or separate computers without affecting other applications, unless mobile Lpars/LDom or cluster technologies with flying zones are used.

The delegation of portions of administrative tasks is possible for containers only. All other technologies require that the tasks be defined exactly and that dedicated roles are assigned. This is costly and time-consuming.

Scalability for separate computers and Lpars is limited based on the hardware (defined performance of the shared interconnect) while domain capacity can be customized by additional hardware. Containers and consolidation on one computer run without adaption of the application on bigger computers. Additional reserves can be used by relocating additional containers to this computer.

Overhead is higher for separate computers and physical and logical partitioning because one operating system with CPU and memory requirements runs per application. Containers and consolidation on one computer share one operating system and are therefore considerably more economical with regard to their consumption of resources. The lower the resource requirements of an application, the more pronounced the effect.

The OS version of each operating system installation must be maintained separately. This means overhead. Therefore, for separate computers as well as physical and logical virtualization, more effort must be expended than for containers or consolidation on one computer. However, multiple OS versions enable the use of different versions of the OS if required by the applications. The assessment in this regard depends on data center policies and operation purposes.

The overhead of several OS instances can be reduced by using management software such as e.g. Sun xVM OpsCenter, which requires a certain investment.

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