Silicon Graphics SGI Altix 3700 Bx2, User Manual

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System Features
007-4377-002 51
System Features
The main features of the Altix 3700 Bx2 series server systems are introduced in the
following sections:
• “Modularity and Scalability” on page 51
• “Distributed Shared Memory (DSM)” on page 51
• “Distributed Shared I/O” on page 52
• “Reliability, Availability, and Serviceability (RAS)” on page 53
Modularity and Scalability
The Altix 3700 Bx2 series systems are modular systems. The components are housed in
building blocks referred to as bricks. You can add different brick types to a system to
achieve the desired system configuration. You can easily configure systems around
processing capability, I/O capability, memory size, or storage capacity. You place
individual bricks that create the basic functionality (compute/memory, I/O, and power)
into custom 19-inch racks. The air-cooled system has redundant, hot-swap fans at the
brick level and redundant, hot-swap power supplies at the rack level.
Distributed Shared Memory (DSM)
In the Altix 3700 Bx2 series server, memory is physically distributed among the
CR-bricks (compute/router nodes); however, it is accessible to and shared by all
CR-bricks within the system. A CR-brick with configured memory but zero processors is
generally referred to as a “memory node” or M-brick.
Note the following types of memory:
• If a processor accesses memory that is connected to the same SHUB ASIC on a
compute node, the memory is referred to as the node’s
local memory .
• If processors access memory located in other nodes, the memory is referred to as
remote memory .
• The total memory within the system is referred to as global memory .
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.