This chapter helps you understand how to read MIB variable descriptions. It covers the following:
Note that the STATUS element of SNMP MIB definition, Version 2, is not included in these MIB variable descriptions. Since Oracle has implemented all MIB variables as CURRENT, this value does not vary.
Maps to the SYNTAX element of SNMP MIB definition, Version 2.
Maps to the MAX-ACCESS element of SNMP MIB definition, Version 2.
Maps to the STATUS element of SNMP MIB definition, Version 2.
Describes the function, use and precise derivation of the variable. (For example, a variable might be derived from a particular configuration file parameter or performance table field.) When appropriate, incorporates the DESCRIPTION part of the MIB definition, Version 2.
Describes the typical, rather than theoretical, range of the variable. For example, while integer values for many MIB variables can theoretically range up to 4294967295, a typical range in an actual installation will vary to a lesser extent. On the other hand, some variable values for a large database can actually exceed this ÒtheoreticalÓ limit (a ÒwraparoundÓ). Specifying that a variable value typically ranges from 0 to 1,000 or 1,000 to 3 billion will help the third-party developer to develop the most useful graphical display for the variable.
Describes the significance of the variable when monitoring a typical installation. Alternative ratings are Very Important, Important, Less Important, or Not Normally Used. Clearly, the DBA will want to monitor some variables more closely than others. However, which variables fall into this category can vary from installation to installation, depending on the application, the size of the database, and on the DBA's objectives. Nevertheless, assessing a variable's significance relative to the other variables in the MIB can help third-party developers focus their efforts on those variables of most interest to the most DBAs.
Lists other variables in this MIB, or other MIBs implemented by Oracle, that relate in some way to this variable. For example, the value of this variable might derive from that of another MIB variable. Or perhaps the value of this variable varies inversely to that of another variable. Knowing this information, third-party developers can develop useful graphic displays of related MIB variables.
Suggests how this variable can be presented most usefully to the DBA using the management application: as a simple value, as a gauge, or as an alarm, for example.
Example 4-1 shows a typical MIB definition used by Enterprise Manager.
ORACLE-ENTERPRISE-MANAGER-4-MIB DEFINITIONS ::= BEGIN IMPORTS TRAP-TYPE FROM RFC-1215 DisplayString FROM RFC1213-MIB OBJECT-TYPE FROM RFC-1212 enterprises FROM RFC1155-SMI; oracle OBJECT IDENTIFIER ::= { enterprises 111 } oraEM4 OBJECT IDENTIFIER ::= { oracle 15 } oraEM4Objects OBJECT IDENTIFIER ::= { oraEM4 1 } oraEM4AlertTable OBJECT-TYPE SYNTAX SEQUENCE OF OraEM4AlertEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "Information on alerts generated by Oracle Enterprise Manager. This table is not queryable; it exists only to document the variables included in the oraEM4Alert trap. Each trap contains a single instance of each variable in the table." ::= { oraEM4Objects 1 } oraEM4AlertEntry OBJECT-TYPE SYNTAX OraEM4AlertEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "Information about a particular Oracle Enterprise Manager alert." INDEX { oraEM4AlertIndex } ::= { oraEM4AlertTable 1 } OraEM4AlertEntry ::= SEQUENCE { oraEM4AlertIndex INTEGER, oraEM4AlertTargetName DisplayString, oraEM4AlertTargetType DisplayString, oraEM4AlertHostName DisplayString, oraEM4AlertMetricName DisplayString, oraEM4AlertKeyName DisplayString, oraEM4AlertKeyValue DisplayString, oraEM4AlertTimeStamp DisplayString, oraEM4AlertSeverity DisplayString, oraEM4AlertMessage DisplayString, oraEM4AlertRuleName DisplayString oraEM4AlertRuleOwner DisplayString } oraEM4AlertIndex OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "Index of a particular alert, unique only at the moment an alert is generated." ::= { oraEM4AlertEntry 1 } oraEM4AlertTargetName OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The name of the target to which this alert applies." ::= { oraEM4AlertEntry 2 } oraEM4AlertTargetType OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The type of the target to which this alert applies." ::= { oraEM4AlertEntry 3 } oraEM4AlertHostName OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The name of the host on which this alert originated." ::= { oraEM4AlertEntry 4 } oraEM4AlertMetricName OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The name of the metric which generated this alert." ::= { oraEM4AlertEntry 5 } oraEM4AlertKeyName OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The name of the key-column, if present, for the metric which generated this alert." ::= { oraEM4AlertEntry 6 } oraEM4AlertKeyValue OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The value of the key-column, if present, for the metric which generated this alert." ::= { oraEM4AlertEntry 7 } oraEM4AlertTimeStamp OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The time at which this alert was generated." ::= { oraEM4AlertEntry 8 } oraEM4AlertSeverity OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The severity of the alert e.g. Critical." ::= { oraEM4AlertEntry 9 } oraEM4AlertMessage OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The message associated with the alert." ::= { oraEM4AlertEntry 10 } oraEM4AlertRuleName OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The name of the notification rule that caused this notification." ::= { oraEM4AlertEntry 11 } oraEM4AlertRuleOwner OBJECT-TYPE SYNTAX DisplayString ACCESS read-only STATUS mandatory DESCRIPTION "The owner of the notification rule that caused this notification." ::= { oraEM4AlertEntry 12 } oraEM4Traps OBJECT IDENTIFIER ::= { oraEM4 2 } oraEM4Alert TRAP-TYPE ENTERPRISE oraEM4Traps VARIABLES { oraEM4AlertTargetName, oraEM4AlertTargetType, oraEM4AlertHostName, oraEM4AlertMetricName, oraEM4AlertKeyName, oraEM4AlertKeyValue, oraEM4AlertTimeStamp, oraEM4AlertSeverity, oraEM4AlertMessage, oraEM4AlertRuleName, oraEM4AlertRuleOwner } DESCRIPTION "The variables included in the oraEM4Alert trap." ::= 1 END