3.7.2 Notes about operations (for AIX)

This subsection provides notes about SNMP Agent operation when the OS in use is AIX. For notes common to all OSs, see 3.7 Notes about operations.

Notes about acquiring the MIB page group in AIX

Depending on the system configuration, an attempt to acquire a MIB belonging to the Hitachi enterprise-specific MIB page group might frequently result in an error. In such a case, measure the runtime of the page.exe command provided by SNMP Agent.

If execution of the page.exe command takes 10 seconds or more, the system cannot acquire the correct page group MIB. If you continue operations in this status, the operating system's command process, which runs in an attempt to acquire page information, will continue to run illegally. This could increase the system workload.

To avoid this problem, edit the page.exe command as shown below. Once this change is made, the command will not execute even when a MIB belonging to the page group has been acquired. Pseudo information indicating page 0 is always returned as the MIB value for the page group.

Before change:
```
lsps -a > $OUTFILE
```
After change:
```
echo
exit 0
```
Notes about the native agent function
- The native agent adapter provided by SNMP Agent (naaagt process) specifies the community name public in the SNMP GET and GET-NEXT requests of SNMPv1 to acquire MIBs from the AIX-provided native agent (snmpd process). This is not a problem because the default settings of the snmpd process in SNMPv1 permit SNMP GET and GET-NEXT requests for the community name public. However, if you change the community name for the snmpd process, make sure that you permit SNMP GET and GET-NEXT requests in SNMPv1. If you have changed the community name for the snmpd process to a value other than public, also change the naaagt process settings. For details about how to change the naaagt process settings, see Configuration file (naa.cnf) in Chapter 6. Definition Files.
- For the snmpd process, you can choose to use snmpdv1 or snmpdv3 via the snmpv3_ssw command provided in AIX. With the AIX default settings, the process uses the snmpdv3 agent.
  
  If you start SNMP Agent and the snmpdv1 or snmpdv3 agent at the same time, conflict occurs on the SNMP reception port (161/udp). You must change the SNMP reception port for the snmpdv1 or snmpdv3 agent. SNMP Agent changes the port based on the snmpdv3 agent that is used by default in AIX. For details about how to change the SNMP reception port, see the AIX documentation.
Notes about avoiding process termination due to a shortage of OS memory

In the event of a shortage of OS memory in AIX, SIGKILL is issued and the process might terminate. To avoid this, set PSALLOC=early in the environment variable of the user that starts SNMP Agent, and then start SNMP Agent. If you set early in the PSALLOC environment variable, also set the NODISCLAIM=true environment variable, and then restart SNMP Agent.

Set the PSALLOC and NODISCLAIM environment variables in the SnmpMaster file.

The following shows an example.

Example:
```
SNMP_MASTER_OPTIONS="-tcplocal"         # Master Agent options
export SNMP_MASTER_OPTIONS
PSALLOC=early
export PSALLOC
NODISCLAIM=true
export NODISCLAIM
```
For notes about the amount of free space in physical memory, see 2.13 Notes about the amount of free space in physical memory.
For notes about CPU usage rate information, see 2.15 Notes about CPU information.

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