Caché Installation Guide - InterSystems Documentation

Calculating System Parameters for OpenVMS
• The memory in a named section is physically contiguous and therefore can be mapped by a single
granularity hint region; this may result in better performance.
The drawback to creating a named reserved section is that if you want to increase the size, you may
have to restart your OpenVMS system to reconfigure the amount of space reserved for the memoryresident
global section. You can reserve this space when the system starts (via SYSMAN and
AUTOGEN) or you can allocate it dynamically. If you do not reserve it, when Caché requests it, there
may be insufficient space available and the request fails. If Caché attempts to use a memory-resident
global section and it cannot, it allocates the global buffer pool out of a non–memory-resident global
section.
Use the Resident Memory value if you want to Reserve a Named Memory-Resident Section for Caché.
A.6.3.1 Reserve a Named Memory-Resident Section
1. Use the value returned by the OpenVMS Parameter Calculator for Resident Memory as the reserved
memory size.
2. Use SYSMAN to reserve a section of memory and supply a name for the named section. You can
use any name that consists of alphanumeric characters (and the underscore) and is not longer than
43 characters. The syntax for SYSMAN is:
MCR SYSMAN ! run sysman
SYSMAN> RESERVED_MEMORY ADD "Resident_Memory_Name" -
/ALLOCATE/PAGE_TABLES/ZERO/SIZE=
SYSMAN> EXIT
3. Run AUTOGEN to process the Reserved Memory Registry data file which contains the information
to establish your memory-resident global section. After the system is restarted, the SYSMAN
command displays the shared memory section you reserved:
MCR SYSMAN ! run sysman
SYSMAN> RESERVED_MEMORY SHOW
4. Update the configuration file by using the System Management Portal that connects to your
OpenVMS Caché instance from a Web server:
a. Navigate to the [Home] > [Configuration] > [Advanced Memory Settings] page.
b. In the useresidentmem (ResidentMemorySectionName) setting row, click Edit.
c. Enter the name you reserved in the SYSMAN utility (Resident_Memory_Name in the
example in step 2) in the Value box and click Save.
Alternately, you can modify the Caché configuration file (cache.cpf) to use the reserved section;
set the reserved memory parameter in the [config] section so that it reads:
useresidentmem=
80 Caché Installation Guide