3 Diagnostics through SNMP Traps

TimesTen and SNMP

TimesTen cannot be queried nor controlled through SNMP. TimesTen only sends SNMP traps for certain critical events, to possibly facilitate some user recovery mechanisms. TimesTen can send traps for the following events:

• Assertion failure

• Death of daemons

• Data store invalid

• Replicated transaction failure

• Data store out of space

• Autorefresh transaction failure

• Replication conflict resolution

• File write errors

These events also cause log entries to be written by the TimesTen daemon, but exposing them through SNMP traps allows for the possibility of having some network management software take immediate action.

SNMP data types

The SNMP data types are either INTEGER or TEXT.

ASN_INTEGER data are:

• ttPid

• ttDSNConn

• ttDSCurSize

• ttDaeInst

• ttRepReceiverPort

• ttDSReqSize

• ttDaePid

• ttDSMaxSize

• ttCacheAgentPid

The rest of the variables are ASN_OCTET_STRING type.

Trapping out of space messages

By default, TimesTen records that data store space is low based on the partition space thresholds of PermWarnThreshold and TempWarnThreshold attributes. If the PermWarnThreshold, which defines the permanent data store memory partition threshold, is set to 90, TimesTen records a message that the permanent data store memory is full. Once the data store permanent memory becomes 10% less than the set threshold, which in this case would be 80% full, TimesTen records a second message indicating that the data store is no longer low on space.

When connecting to a data store, you can change the out of space threshold by setting the PermWarnThreshold and TempWarnThreshold attributes. See "PermWarnThreshold" and "TempWarnThreshold" in Oracle TimesTen In-Memory Database Reference.

How TimesTen sends SNMP traps

SNMP traps are UDP/IP packets. Therefore, there is no guarantee of delivery, and it is not an error if there are no subscribers for the trap. TimesTen sends only SNMPv1 traps, which all network management systems should understand.

Generating SNMP traps

To enable SNMP trap generation, remove the line -enabled 0 in the snmp.ini file, or change 0 to 1 on that line. TimesTen does not generate SNMP traps by default because, in the case of repeated failures, such as an application that continues to attempt to insert new rows into a full data store, the application may experience a performance slowdown due to generation of SNMP traps.

Configuring the snmp.ini file

For root installations, the configuration file /var/TimesTen/snmp.ini on UNIX systems and install_dir\srv\info\snmp.ini on Windows systems enables or disables trap generation, controls the community string for SNMP traps, the target host and the target port on which to listen for traps.

The file contents are:

An optional environment variable, TT_SNMP_INI, can override the location of the snmp.ini file. If this variable is set, it should contain the full path of the SNMP sender configuration file, which can have a name other than snmp.ini.

#Enable SNMP trap generation
-enabled 1
#Default community is "public"
-community "public"
#Default trap destination is "localhost" and default destination SNMP trap port is 162
-trapdest "localhost:162"

#Enable SNMP trap generation
-enabled 0
#Default community is "public"
-community "public"
#Default trap destination is "localhost" and default destination SNMP trap port is 162
-trapdest "localhost:162"
-trapdest "pluto:10999"
-trapdest "mymachine:189"

#Disable SNMP trap generation
-enabled 0
#Default community is "public"
-community "public"
#Default trap destination is "localhost" and default destination SNMP trap port is 162
-trapdest "localhost:162"

Receiving SNMP traps

You must have network management software to receive SNMP traps.

For demonstration purposes, TimesTen ships the program install_dir/demo/snmp/snmptrapd, which listens for SNMP traps and prints them out or logs them to a file. Read the install_dir/demo/snmp/README file for details on how to run this program.

Trap truncation on overflow

The maximum packet size of a single trap is 1024 bytes. If there is more data than can fit into the 1024 byte limit, the trap is truncated to fit. In this case, the trap contains a ttTrapTruncated OID set to 1.

The TimesTen MIB

A Management Information Base (MIB) is like a database schema. It describes the structure of the SNMP data. For more information about MIBs in general, please refer to the previously mentioned SNMP overview documents.

The MIB extension file, install_dir/mibs/TimesTen-MIB.txt, describes the structure of the TimesTen SNMP information.

The TimesTen OID is rooted at Private Enterprise 5549. The complete path to root is iso.org.dod.internet.private.enterprise.TimesTen.* or numerically, 1.3.6.1.4.1.5549.*.

The traps

Every trap has a GMT timestamp of when the trap occurred, as well as the Process ID, user name (or User ID on UNIX systems) of the process, TimesTen instance name, TimesTen, release number and a trap specific Message. In addition, most traps provide additional information specific to that message. For example the ttRepAgentDiedTrap also provides the Replication Store ID. For a list of the variables for each trap see the TimesTen-MIB.txt file.

Trap names and severity levels

TimesTen SNMP traps can be categorized by severity level. The information in the trap can be of the type:

• Informational

• Warning

• Error

The following table describes each trap and its severity level.

Example

A typical TimesTen trap, printed with snmptrapd, looks like this:

Enterprise Specific Trap (ttDSGoingInvalidTrap) Uptime: 4:34:16
enterprises.timesten.ttSystem.ttTimeStamp = "2002-07-20 22:24:49 (GMT)"
enterprises.timesten.ttSystem.ttPid = 127
enterprises.timesten.ttSystem.ttUid = "SYSTEM"
enterprises.timesten.ttSystem.ttVersion = "@(#) TimesTen Revision: 11.2.1.0.0 Date: 2008/07/07 18:24:10, instance giraffe"
enterprises.timesten.ttMsg, ttMesg "Data store going Invalid (from master daemon)"
enterprises.timesten.ttDataStore.ttDSName = "tptbmdata1121"
enterprises.timesten.ttDataStore.ttDSShmKey = "DBI39775920.0.SHM.12"
enterprises.timesten.ttDataStore.ttDSNConn = 2

This trap was generated from a TimesTen daemon running on a Windows system. The hostname of the system sending the trap is printed by snmptrapd. The Uptime field, which is required by SNMP, lists the elapsed time since the start of the process which generated this trap. In this case, the process ttsrv1121.exe has been running for 4 hours, 34 minutes, and 16 seconds.

This specific trap is for the Database going invalid event. So additionally, it reports the data store name, shared memory key of the data store and the number of current connections to the data store.