Specifications

BIOS Initialization QSSC-S4R Technical Product Specification

148

Note: The arrow points from Primary to Secondary

Copy of Memory Data

CPU1

MEM3_SLOT MEM4_SLOTMEM1_SLOT MEM2_SLOT

CPU4CPU3

MEM7_SLOT MEM8_SLOTMEM5_SLOT MEM6_SLOT

CPU2

Figure 73. Mirroring in Hemisphere Mode

16.2.11 Memory Hot-Plug

Memory Hot-plug is the ability to upgrade the system memory at runtime while the operating system is running, without

the need for bringing down the system. Memory in QSSC-S4R platform is populated using eight memory boards.

Memory Hot-plug is performed at the memory board level. It is not supported on individual DIMM level. Each memory

board has a set of elements (buttons and indicators) that are associated with hot-pluggable slots or devices, similar to

PCI Express Hot-plug described in the PCI Express Base Specification, v 2.0. The QSSC-S4R platform has additional

hot-plug hardware that assist in supporting hot-plug of each memory board. Each memory board has a mirror LED to

indicate whether mirroring is active or disabled/failed. Only one memory board may be hot-plugged at a time. There are

two distinct Memory Hot-plug operations supported:

x Memory hot-replace in the Mirrored mode

x Memory Hot-add

Memory hot replacement is the ability to replace the memory on a failing memory board with equivalent new memory.

To achieve this, the affected memory board must be mirrored with another memory board. Memory hot-replace does

not alter overall memory capacity.

The BIOS provides setup options to enable memory mirroring between memory boards.

The QSSC-S4R platform also supports the hot addition of memory boards on empty memory board slots to increase

capacity. The hot addition of memory is called “Capacity Add” and requires OS support to accommodate and utilize the

additional memory.

Memory hot-removal in the non-mirroring mode, which results in capacity reduction, is not supported, as there is no OS

support available for this feature.

NUMA should be enabled in BIOS setup if user wants to perform memory hot plug operation in runtime.