Logical Partitioning Of Memory - Hitachi Compute Blade 500 Series User Manual

Logical Partitioning of Memory

The memory size to be allocated to each LPAR can be specified for each LPAR
(in multiples of 256 MB). Each guest OS has an exclusive use of the memory
assigned to its LPAR. LPAR manager automatically determines which physical
memory offset area(s) to allocate to an LPAR when the LPAR is activated.
• Memory for LPAR manager
LPAR manager on CB 520H A1/B1/B2 / CB 520A A1 / CB 540A A1/B1
uses 2048 MB of the physical memory installed. LPAR manager on CB
520H B3 uses 2560 MB of the physical memory installed. And LPAR
manager on CB 520X B1/B2 uses 3072 MB of the physical memory
installed.
• Memory for logical firmware
Logical firmware uses a part of memory space assigned to each LPAR.
Memory that logical firmware uses, in general, can be estimated from the
following calculation formulas:
– [Less than 8 GB memory assigned to LPAR]
¢
– [8 GB or larger memory assigned to LPAR]
¢
• Memory for a guest OS
Memory space available for a guest OS is calculated by subtracting the
amount of memory the logical firmware uses from the amount assigned
to the LPAR. This memory size is usually same as the available memory
size for a guest OS (indicated memory size in a guest OS). However, all
allocated memory size may not be available depending on the
specification and environment of guest OS.
Note:
• When the amount of memory for a guest OS is not enough against the
amount applications use, memory swap may happen to cause
performance degradation. When assigning an amount of memory, make
sure to take the memory amount.
Hitachi Compute Blade 500 Series Logical partitioning manager User's Guide
Figure 1-18 Memory Mapping of Logical Partitioning
0.6% of memory assigned to LPAR + number of logical processors x
2.25 MB + 65 MB
0.25% of memory assigned to LPAR + number of logical processors x
2.25 MB + 80 MB
LPAR manager Functions
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