Introduction to Virtualization - Oracle Solaris 10 System Virtualization Essentials - page 30

Figure 1.18 Dynamic Reallocation of Hardware Resources
1.2.1.4 Scalability
Two related types of scalability exist in the context of system virtualization: guest
scalability and per-VE performance scalability. Guest scalability is the number of
VEs that can run on the system without significantly interfering with one another.
Hard partitions are limited by the number of CPUs or CPU boards in the system,
but can also be limited by other hardware factors. For some of these systems, only
2 partitions can be configured for each system. For others, as many as 24 parti-
tions can reside in the system.
Because these systems are generally intended to perform well with dozens of
CPUs in a single system image, they usually run large workloads on a small num-
ber of partitions. Their value derives from their combination of resource flexibil-
ity, failure isolation, and per-VE performance scalability.
Because hard partitioning does not require an extra layer of software, there
should be no performance overhead inherent in this type of virtualization.
Applications will run with the same performance as in a nonpartitioned system
with the same hardware.
1.2.1.5 Partition Management
Hardware isolation requires specialized hardware. This requirement usually in-
cludes components that aid in the management of the partitions, including the
configuration of hardware resources into those partitions. These components may
also assist in the installation, basic management, and health monitoring of the
OS instances running on the partitions. Specialized ASICs control data paths and
enforce partition isolation.