Information Technology Reference
In-Depth Information
Architects choosing virtualization technologies to meet an application's re-
quirements take all of the previously mentioned factors into consideration, map-
ping requirements onto the combinations of technologies that best meet them.
The following sections describe the virtualization technologies under discussion
in this context.
As described in Chapter 2, “Hard Partitioning: Dynamic Domains,” Dynamic
Domains are a feature of the Sun SPARC Enterprise M9000 servers providing
isolated hardware environments, each of which runs its own copy of the Oracle
Solaris operating system. This technology has the following strengths:
Best fault isolation.
No failure in one domain or in its infrastructure can
affect another. Other solutions carry with them the risk that a failure occur-
ring in one VE will affect other VEs, perhaps even causing them all to halt.
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Security isolation.
A security penetration or compromise in one domain
has no effect on other domains.
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Complete compatibility in every respect with non-domained envi-
ronments.
There is no concern about incompatibility or non-supportability
of software.
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Native performance compared to non-domained environments.
There is no virtualization layer. The CPU code path of an application is not
elongated by virtualization, and no additional firmware is needed to assist
with virtualization. This advantage, compared to software hypervisors, is
greatest for I/O intensive applications.
However, domain scalability is limited by hardware capabilities. The
highest scalability is provided by Sun M9000 systems, which currently can
have a maximum of 24 Dynamic Domains.
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Completely separate Oracle Solaris instances.
Each instance can po-
tentially have its own OS version, patch levels, and maintenance windows
without any conflict or interference. Management of a single domain is the
same as management of a single system. This is similar to hypervisor solu-
tions, but is often an advantage compared to OS virtualization (OSV).
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No extra license fees needed.
This technology is included with all domain-
capable systems. Some hypervisors require a fee for use, or a fee for support
in addition to support fees for the guest operating systems.
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Well-established and -accepted history.
There is more than a decade of
deployment and experience with hard partitioning in the SPARC product line.
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