Information Technology Reference
In-Depth Information
Network devices
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Disks
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Console
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OpenBoot environment
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Cryptographic accelerators (optional)
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The next several sections describe properties of Logical Domains and explain
how they are implemented.
Each domain runs its own instance of Oracle Solaris 10 or OpenSolaris with its own
accounts, passwords, and patch levels, just as if each had its own separate physical
server. Different Solaris patch and update levels run at the same time on the same
server without conflict. Some Linux distributions can also run in domains. Logical
Domains support was added to the Linux source tree at the 2.6.23 level.
Domains are isolated from one another. Thus each domain is individually and
independently started and stopped. As a consequence, a failure in one domain—
even a kernel panic or CPU thread failure—has no effect on other domains, just
as would be the case for Solaris running on multiple servers.
Oracle Solaris and applications in a domain are highly compatible with Solaris
running on a physical server. Solaris has long had a binary compatibility guaran-
tee; this guarantee has been extended to Logical Domains, making no distinction
between running as a guest or on bare metal. Solaris functions essentially the
same in a domain as on a nonvirtualized system.
One of the distinguishing features of Logical Domains compared to other hy-
pervisors is the assignment of CPUs to individual domains. This approach has
a dramatic benefit in terms of increasing simplicity and reducing the overhead
commonly encountered with hypervisor systems.
Traditional hypervisors time-slice physical CPUs among multiple virtual ma-
chines in an effort to provide CPU resources. Time-slicing was necessary because
the number of physical CPUs was relatively small compared to the desired num-
ber of virtual machines. The hypervisor also intercepted and emulated privileged
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