Re: tnsnames vs nameserver

It's how the clients will resolve database names (somtimes called connect strings or services) into addresses. TNSNAMES uses a flat file (tnsnames.ora) accessed directly by the client. It can be on the client or on a shared network drive. Oracle Names is a program that runs on a server and provides exactly the same service.

If you're familiar with tcp/ip, tnsnames.ora serves the same purpose for SQL*Net as a hosts file does for TCP/IP. Oracle Names is like DNS.

If I were setting up a new network my first choice would be Oracle Names. It provides a centralized point of administration for the entire SQL*Net network. I'd also set up more than one names server just in case the primary one goes down. Also, since it's tcp/ip based, it can be used by PCs as well as Unix systems. It also provides a few other benefits. For one, there's less maintenance. New database listeners and their related instances automatically register themselves with the names servers if you're using at least sql*net version 2.3.4. You also automatically get database links created for all other servers also registered with an Oracle Names server.

Second choice would be tnsnames.ora on a networked drive. This also provides centralized administration but without fallback should the server go down. And if it does go down, you're unable to connect to Oracle from any workstation in the network. There's no automatic registering of new listeners and instances and no automatic creation of database links.

Final choice is tnsnames.ora on each PC. It eliminates the single point of failure with the 2nd choice, but creates is more difficult to administer. Changes to the network require you to distribute the new tnsnames.ora file to every client.

        Chuck Hamilton

On Thu, 07 Jan 1999 15:43:16 -0500, Rob Williamson <robw_at_physics.umd.edu> wrote:

>We are about to have an Oracle 8 install done and we were told we needed
>to decide
>on tnsnames ( flat file ) or nameserver ( database ) for the Net8
>install.
>What does this mean? And how should we decide?
>Is it based on how many users we will have?

--
Chuck Hamilton
chuckh_at_safeaccess.net

Never share a foxhole with anyone braver than yourself! Received on Mon Jan 11 1999 - 09:23:49 CST