Greetings all,
I have an Entity Bean in a cluster, pointing to a primary database. However I also have a replicated secondary DB in case the primary goes down. How do I dynamically make my Entity Bean switch to the secondary DB? What cd be the issues involved?
Is this possible in any specific App server, or via some design pattern, or am I barking up the wrong tree ?? ;)
thx in advance,
S.
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database failover for Entity Beans (7 messages)
- Posted by: sabyasachi chakravarty
- Posted on: January 01 2003 00:47 EST
Threaded Messages (7)
- database failover for Entity Beans by Tomas Inger on January 01 2003 09:44 EST
- database failover for Entity Beans by Ferhat SAVCI on January 02 2003 03:12 EST
- database failover for Entity Beans by sabyasachi chakravarty on January 07 2003 00:03 EST
- database failover for Entity Beans by Abhijit Gaikwad on January 02 2003 05:33 EST
- database failover for Entity Beans by sabyasachi chakravarty on January 07 2003 00:06 EST
- database failover for Entity Beans by Venkat Subramani on January 02 2003 15:01 EST
- database failover for Entity Beans by rajesh s r on January 03 2003 00:25 EST
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database failover for Entity Beans[ Go to top ]
- Posted by: Tomas Inger
- Posted on: January 01 2003 09:44 EST
- in response to sabyasachi chakravarty
Hi!
I think the best way is to solve this problem on the database side, adn not involve the application server at all. This can be done by having two database servers behind hardware switches. If you have an Oracle database, I know such solutions exist.
The application server will speak to one IP address (physicaly the switch) and the database will look like single machine.
This will cost you some hardware, but you avoid software implementation of a standard problem. You will save money in implementation, but most of all when maintaining the code.
/Tomas -
database failover for Entity Beans[ Go to top ]
- Posted by: Ferhat SAVCI
- Posted on: January 02 2003 03:12 EST
- in response to Tomas Inger
Fail-over cluster software running in hot-standby mode does that for any database (or any server software, for that matter), but, I was not aware of a hardware solution. Which kind of switch are we talking about? L7 content-switches?
Could you name the vendor and the model for Oracle?
I have a few clients who are paying big bucks for cluster software licenses annually and naturally do not like it. -
database failover for Entity Beans[ Go to top ]
- Posted by: sabyasachi chakravarty
- Posted on: January 07 2003 00:03 EST
- in response to Tomas Inger
In this case, the issue I belive wd be to maintain consistency of data, as the transactions may be talking to either of the databases. -
database failover for Entity Beans[ Go to top ]
- Posted by: Abhijit Gaikwad
- Posted on: January 02 2003 05:33 EST
- in response to sabyasachi chakravarty
Hi ,
Transparent Application Failover (TAF) or simply Application Failover is a feature of the OCI driver. It automatically reconnects to a database if the database instance to which the connection is made goes down. The link illustrates the Support for TAF in JDBC OCI Drivers. It also illustrates the registration and operation of Oracle JDBC OCI application failover callbacks with the help of call back functions.
Link is as follows,
http://technet.oracle.com/sample_code/tech/java/sqlj_jdbc/files/9i_jdbc/OCIdriverTAFSample/OCIdriverTAFSample.jar
Hope this helps.
Regards,
@bhijit -
database failover for Entity Beans[ Go to top ]
- Posted by: sabyasachi chakravarty
- Posted on: January 07 2003 00:06 EST
- in response to Abhijit Gaikwad
In this case, my concern is that the database may be down for say 10-15 mts, during which though the connection is retried again it will still fail. However I wd like to maintain continuity of business and if need be connect to a replicated DB. Does the Transparent Application Failover feature allow connecting to another DB? -
database failover for Entity Beans[ Go to top ]
- Posted by: Venkat Subramani
- Posted on: January 02 2003 15:01 EST
- in response to sabyasachi chakravarty
WebLogic 7.0 has a feature called multipools which
is a pool of JDBC pools .
If one of the pool loses connection to DB, multipool
would automatically switch to the other pool pointing
to the backup database. -
database failover for Entity Beans[ Go to top ]
- Posted by: rajesh s r
- Posted on: January 03 2003 00:25 EST
- in response to Venkat Subramani
Multipools in WLS 7.0 cannot be used in a cluster setup. Using multipools may also cause other problems like synchronization/replication of the different databases. The best way is to solve it in the DB side, but will be incurring higher cost.