HP 9000 V2500 SCA, Operator'S Manual

Page: 32 / 206

10 Chapter 1
Overview
V-Class Server Architecture
Three DIMM sizes are supported for use in V2500/V2600 servers:
32 MByte, 128 MByte, and 256 MByte. Only specified mixed DIMM size
configurations are supported.
If planning for a multiple-cabinet server configuration, you must use 88-
bit DIMMs and configure your V2500/V2600 server to be one-fourth, one-
half, or fully populated with DIMMs.
Single-cabinet servers can instead use 80-bit DIMMs and may also be
filled to three-fourths memory capacity (3 DIMMs in every quadrant).
As Figure 8 shows, each memory board includes a memory access
controller, memory DIMMs, and a CTI controller. The CTI controller is
not used in single-cabinet servers, but is present for connecting cabinets
in multiple-cabinet servers. Details on multiple-cabinet CTI connections
are available in “Multiple-Cabinet Server Connections” on page 15.
Figure 8 Conceptual Overview of V2500/V2600 Memory Board
The V-Class cabinet has a Symmetric Multi-Processing (SMP) design,
which gives all processors equal access to all memory and a uniform
latency for memory accesses.
Multiple-cabinet V2500/V2600 servers include memory on all cabinets.
This provides SMP-like access to memory that resides on the same
cabinet as the requesting processor and gives the whole system a cache-
coherent non-uniform memory (ccNUMA) architecture. By dedicating
some memory as “CTI cache” memory, you can enhance performance by
allowing frequently used data that resides in memory on remote cabinets
to be encached on the local cabinet. See “CTI Cache Memory” on page 11.
Memory
CTI
Memory
Controller
(to crossbar)
(X-dimension
cabinet connection)
(Y-dimension
cabinet connection)