Let's say I install DB2 Connect product and catalog remote databases (local db's are on zOS). Does the DB2 Connect instance need to be started in order to connect to the remote db?

We have v8 installed on the server ( ESE which includes DB2 Connect for 5 users). It has a bunch of remote databases catalogued, all pointing to db's on zOS. I wanted to test if the application can connect directly to zOS (just using the JAR files). I stopped the instance and renamed the node and db directory files. The connection failed with sql1031n. I put the node/catalog files back and the connection worked (with instance staying down). It looks like the instance doesn't need to be started for remote connection. What's the purpose of creating an instance in this case? Just to catalog the node/db?

The JDBC driver does not need the Connect instance to be running, as it implements the correct protocol to talk to System Z.

CLI applications, I believe, do need the Connect instance to translate the protocol. You can easily verify that by trying to connect to a host database using DB2 CLP while the Connect instance is down.

Connection from CLP works ( the instance is down )

$ db2 connect to xxxx user yyyy
Enter current password for yyyy:

Database Connection Information

Database server = DB2 MVS 1.0
SQL authorization ID = yyyy
Local database alias = xxxx


What does CLP use to connect to zOS?

It's a CLI application, if that's what you're asking.

I guess it can work when running on the actual Connect server, but clearly you'd need the instance up and running when connecting a remote client.

Is there some way I can check if the application is CLI or Java? I see the followiing in some dbconfig file for this application:


I have no idea what all this means, but I guess DB2CLI means it's a CLI application? Is there some other way I can tell? The application connects to zOS so there is nothing listed in list applications or list dcs applications output.