How does NetWare 6.x use memory above 4Gb?

(Last modified: 09Jun2003)

This document (10069653) is provided subject to the disclaimer at the end of this document.

goal

How does NetWare 6.0/6.5 memory above 4Gb?

fact

Novell NetWare 6.0

Novell NetWare 6.5

fix

Memory above 4Gb will only be used by NetWare as Virtual Memory in NetWare 6.0 and as NSS Cache/Virtual Memory in NetWare 6.5

cause

NetWare 6.0 requires a minimum of 256 Mb of RAM and can access up to 64 Gb of RAM. 

After the SERVER.EXE file is loaded, all remaining memory below 4 GB is assigned to cache memory and virtual memory, which is available for NetWare Loadable ModuleTM (NLMTM) programs and other processes to use. The memory allocator will allocate only up to 4 GB of memory to cache memory and the remaining will be using by the virtual memory system.

In NetWare 6.0 the Virtual memory subsystem maximum size is 480 Mb.

NetWare 6.5 requires a minimum of 512 Mb of RAM and can access up to 64 Gb of RAM.

In addition to VM, NSS in NetWare 6.5 can consume memory above 4Gb for file cache as per the NSS parameter 'NSS /Above4GigMemoryPercent'.  Due to the expensive nature of accessing memory above 4Gb in current Intel architecture NSS will only cache files above 128Kb in size in memory above 4Gb.

In NetWare 6.5 the Virtual memory subsystem maximum size is 1 Gb however can be increased with the 'server -u' load time parameter.

Protected Address Space
A portion of the logical address space is set aside for protected address spaces (sometimes called user address spaces or ring 3). This protected address space is a portion of the logical address space that has carefully controlled interaction with the server operating system. Modules that load into a protected address space can't corrupt the operating system or cause server abends, the protected address space provides a safe place to run applications.  All protected address spaces use virtual memory.

Virtual Memory
NetWare provides a virtual memory system that swaps little-used data to disk, thereby freeing memory for more frequently used data. Applications that run in protected address spaces use virtual memory, as does Java*. The following shows the amount memory the server can recognize and what portions the virtual memory system uses.

0GB - 64GB
Memory the server operating system can recognise.

0GB - 4GB
This is memory that is used by the files system , NLMs and device drivers and can be shared with the virtual memory system.

4GB - 64GB
Memory used only by the virtual memory system or Extended Server Memory (ESM) Windows APIs.

fix

Loading Protected Address Spaces

Load one module into the next available protected address space:
[LOAD] PROTECTED module_name
For example:
[LOAD] PROTECTED DATABASE.NLM

Load one module into a protected space with a user-defined name:
LOAD] ADDRESS SPACE = space_name module_name
For example:
[LOAD] ADDRESS SPACE = DB_SPACE DATABASE.NLM

For more information, consult the Online Documentation

document

Document Title:	How does NetWare 6.x use memory above 4Gb?
Document ID:	10069653
Solution ID:	NOVL75630
Creation Date:	01Apr2002
Modified Date:	09Jun2003
Novell Product Class:	NetWare

disclaimer

The Origin of this information may be internal or external to Novell. Novell makes all reasonable efforts to verify this information. However, the information provided in this document is for your information only. Novell makes no explicit or implied claims to the validity of this information.
Any trademarks referenced in this document are the property of their respective owners. Consult your product manuals for complete trademark information.