Chapter 4 Load Balancing, Failover, and Component Availability

Implementing Sybase Failover for high availability systems

You can implement the Sybase Failover for High Availability Systems (failover) feature in Adaptive Server Enterprise 12.0 with Jaguar server database connectivity using Java Connection Management (JCM).

You configure JCM by enabling Java Database Connectivity (JDBC) connections to establish failover-enabled connections to Adaptive Server Enterprise 12.0. jConnect requires that the connection's attributes be configured on an LDAP server and accessed using JNDI. See the jConnect and JNDI documentation for more details on the jConnect configuration for LDAP.

jConnect 4.2 (EBF 8719 or later) and JNDI 1.2 are required. You can download jConnect 4.2 (EBF 8719 or later) from http://www.sybase.com/products/internet/jconnect/jdbcreg42_52.html

You can implement failover using either:

JDBC 1.0 and 2.0

To set up jConnect to access LDAP and JNDI with JDBC 1.0 and JDBC 2.0 connections, you must:

In the examples in this section, you must enter the text of an indented line on the same line as the previous one.

Configure LDAP

To configure LDAP, run your Jaguar server with JDK 1.2 and use your LDAP software to set up an LDAP entry of the form:

servername=primaryserver, o=Sybase, c=US
1.3.6.1.4.1.897.4.2.5: TCP#1#hostname portnum
1.3.6.1.4.1.897.4.2.10: REQUEST_HA_SESSION=true
1.3.6.1.4.1.897.4.2.15:servername=secondaryserver,o=Sybase, c=US
servername=secondaryserver, o=Sybase, c=US1.3.6.1.4.1.897.4.2.5: 
   TCP#1#aeon 9898

Configure a connection cache

Use Jaguar Manager to configure the connection cache with these values for the specified properties:

Username: DBuid
Passwd: DBpasswd
Connection URL (servername): jdbc:sybase:jndi:ldap://<ldapserver>:<ldapport> /servername=primaryserver;o=Sybase;c=US

You must specify a semicolon (;) as the field separator in the Connection URL field.

Changing the default values or adding properties

To change the default values or specify additional properties that Jaguar uses for LDAP server configuration, you can create <cachename>.props files in the $JAGUAR/Repository/ConnCache directory as shown in the following example:

cachename.props:
java.naming.factory.initial=com.sun.jndi.ldap.
    LdapCtxFactory
java.naming.factory.object=com.sybase.jdbc2.jdbc.
    SybObjectFactory
java.naming.provider.url=ldap://duplo:389/o=Sybase,
    c=US

where duplo:389 is the port where the LDAP server is running. The values listed for the first two properties are the defaults used by Jaguar.

After creating this file, you must specify the java.naming.provider.url.

JDBC 2.0 extn/JTA drivers

You set up JDBC 2.0 extn / JTA drivers as follows:

Configure LDAP

Using your LDAP software, set up an LDAP entry of the form:

servername=serverwithxa, o=Sybase, c=US
1.3.6.1.4.1.897.4.2.5: TCP#1#hostname portnum
1.3.6.1.4.1.897.4.2.10: REQUEST_HA_SESSION=true
1.3.6.1.4.1.897.4.2.18: XADataSource
1.3.6.1.4.1.897.4.2.15: servername=secondarywithxa,
    o=Sybase, c=US
servername=serverwithxa, o=Sybase, c=US
    1.3.6.1.4.1.897.4.2.18: XADataSource
    1.3.6.1.4.1.897.4.2.5: TCP#1#aeon 9898

Configure an XA resource

Use Jaguar Manager to configure the XA resource with these values for the specified properties:

Username: DBuid
Passwd: DBpasswd
Connection URL (servername): LdapLookup=ldap://<ldapserver>:<ldapport>/servername= primarywithxa;o=Sybase;c=US

You must specify a semicolon (;) as the field separator in the Connection URL field.

Troubleshooting the database connection

To find out if your database connection to the LDAP server is working, ping the connection cache.

To ping the connection cache:

Right-click on the connection cache and select Connection Cache Properties.
Click Ping.

If the server does not respond or an error occurs, make sure that:

The CLASSPATH and BOOTCLASSPATH specify the correct locations for the ldap.jar, providerutil.jar, jconn2.jar (the jConnect driver), and jndi.jar (JNDI 1.2)
You are using JDK 1.2.