The main memory is distributed between BS2000 and domain 0 (Dom0) or X2000 (I/O processors).
A recommendation for the main memory configuration of x86 servers which is appropriate for most applications is shown in section "Standard values for x86 servers". The x86 server standard models offered are delivered with this recommended memory configuration.
In most cases the default settings for main memory management do not need to be changed. Expansion of the main memory needs to be considered in the following cases:
Expansion of the entire main memory
When multiple guest systems are used, the size of the entire main memory must be selected to ensure that the total main memory requirement of all guest systems which operate in parallel does not exceed the total main memory which is available. The main proportion of memory for Dom0/X2000 must also be taken into account here, see also the example in section "Standard values for x86 servers".
Main memory size of BS2000
For each VM with a BS2000 guest system at least 512 MB of main memory is required for the guest system and micro kernel together. The main memory required by the applications is not included in this figure. The total main memory required for a guest system depends largely on the applications and the performance required, Use of an extremely large number of or of extremely large tasks or processes always calls for a larger main memory configuration.
JIT buffer
The JIT buffer requirement for the JIT compiler must be borne in mind. By default, 40% of the BS2000 main memory is reserved for this purpose. This memory is not directly available to the operating system and applications.
Further information is provided in section "Controlling buffer sizes of the x86 hardware (CISC)".