User guide

System Features
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System Features
The main features of the SGI UV 2000 series server systems are discussed in the following
sections:
• “Modularity and Scalability” on page 39
• “Distributed Shared Memory (DSM)” on page 39
• “Chassis Management Controller (CMC)” on page 41
• “Distributed Shared I/O” on page 41
• “Reliability, Availability, and Serviceability (RAS)” on page 42
Modularity and Scalability
The SGI UV 2000 series systems are modular systems. The components are primarily housed in
building blocks referred to as individual rack units (IRUs). Additional optional mass storage may
be added to the rack along with additional IRUs. You can add different types of blade options to
a system IRU to achieve the desired system configuration. You can easily configure systems
around processing capability, I/O capability, memory size, or storage capacity. The air-cooled
IRU enclosure system has redundant, hot-swap fans and redundant, hot-swap power supplies.
Distributed Shared Memory (DSM)
In the SGI UV 2000 series server, memory is physically distributed both within and among the
IRU enclosures (compute/memory/I/O blades); however, it is accessible to and shared by all
NUMAlinked devices within the single-system image (SSI). This is to say that all NUMAlinked
components sharing a single Linux operating system, operate and share the memory “fabric” of
the system. Memory latency is the amount of time required for a processor to retrieve data from
memory. Memory latency is lowest when a processor accesses local memory. Note the following
sub-types of memory within a system:
• If a processor accesses memory that it is connected to on a compute node blade, the memory
is referred to as the node’s local memory. Figure 3-4 on page 40 shows a conceptual block
diagram of the blade’s memory, compute and I/O pathways.
• If processors access memory located in other blade nodes within the IRU, (or other
NUMAlinked IRUs) the memory is referred to as remote memory.
• The total memory within the NUMAlinked system is referred to as global memory.