Tuesday, July 6, 2010

Oracle Internet Directory LDAP Relpica States in Fusion Middleware 11g


Oracle Internet Directory LDAP Relpica States in Fusion Middleware 11g (11.1.1)

In the Oracle Fusion Middleware 11g Documentation (I think I was referring to Version 11.1.1 of the doco), you can find OID Administrator’s Guide. As the name suggests, this is the top most important and valuable guide for Oracle Internet Directory Administrators. I think I have read most of this guide already. However I still refer this guide, since there is a lot of information provided in this guide (and it is a reference guide too).
I want to write about the LDAP Replica states mentioned in the Appendix D (How Replication Works) of this Guide. In Fusion middleware, Oracle provides lot of details about Oracle Internet Directory Replication. Earlier this information was scattered around the Oracle Support Website and was difficult to find. Now, I think Oracle collected most of this information in this guide.
If you are working or supporting or planning to implement an OID Replication High Availability environment, then you should be familiar with this section of the topic in the guide. This replica states information will be useful if you are running LDAP Based Replica (Just to refresh your memory, there are two types of Replication possible, ASR based and LDAP Based – ASR is based on Ddatabase Links, while LDAP based replication uses a LDAP Client process).

orclReplicaState Attribute

orclReplicaState attribute stores the Replication State for the LDAP Based Replication Replica. You can check the current Replica State of the OID using the ldapsearch command. (In a Live System that uses LDAP based replication, it will be set to the numeric value of 1 – which means it is in online state).
You need to run the following LDAPSEARCH and check the orclreplicastate attribute as shown below. Please make sure to replace values for the arguments specific to your site, I just gave an example.
ldapsearch -h localhost -p 389 -D cn=orcladmin -w password -b “orclreplicaid=local_replica_ID, cn=replication configuration” -s sub objectclass=*
You need to check the value of the orclreplicastate in the output. Alternatively, you can get the orclreplicastate attribute value directly as shown below example:
ldapsearch -h localhost -p 389 -D cn=orcladmin -w password -b “orclreplicaid=local_replica_ID, cn=replication configuration” -s sub objectclass=* orclreplicastate
The local_replica_ID is specific to your installation, normally it is machine_database. You can check the value using a ldapsearch query as shown below.
Ldapsearch Argument Description:
ArgumentDescription
-hHostname or IP Address of the LDAP Directory ServerI used localhost since I am running this command on the same server where OID is running.
-pPort Number for the LDAP Directory, default LDAP port is 389, LDAPS port is 636.If you use the port 636, then you should define the –U argument.
-DBind DN – LDAP DN for connecting to LDAP Directory
-wPassword for the Bind DN – It is site specific.
-bBase DN for the search – here it starts from the top.
-s baseSearch Scope is base (other values are sub and one)

orclReplicaState possible values in 11g

There are 9 LDAP Replica States mentioned in this guide (In 10g OID, there are only 7 LDAP Replica states, it looks like Oracle added two more LDAP Replica states in 11.1.1). As I mentioned earlier, in a normal production system which uses LDAP based replication, the orclreplicastate will be set to the value of 1 automatically during the start of the replication server first time.
Let’s list the LDAP replica states:
LDAP Replica StateDescription
0Bootstrap - This is one of the important Value. You can setup a new LDAP based consumer replica using this value. Lets talk about it in next blog
1Online – For regular replication processing.
2Offline
3Bootstrap in progress
4Bootstrap in progress + cn=orclcontext completed
5Bootstrap completed with failures
6Database based
7Sync Schema only (Not Data)
8Bootstrap without schema sync (Only Data)
In a LDAP replication with high-availability environment, it is a must that you should understand these values and their significance. Let’s talk about these values and how we can exploit this attribute and their values in the coming blogs. Until then

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