Subject Re: [firebird-support] Running Firebird v1.5 and Firebird 2.0 on one server
Author Helen Borrie
At 05:30 AM 24/12/2009, you wrote:
>I have read some tutorials about running several Firebird Instances on one server. I understand that with a V2.0 server running as a service(DefaultInstance) I only can start firebird v1.56 as an application (with an own port).
>The v2.0 server is installed by somebody else (on a client server) and can't be touched.
>The tutorials say, we should drop the FIREBIRD environment variable.
>Still there is the registry key "HKLM\...\Instances" with the string value "DefaultInstances".
>Now on connect a database with the 1.5 server (own port), Firebird seem to look for the userdatabase (security.fdb) within the path defined by "DefaultInstances". This is wrong because it finds only a security2.fdb there.
>How is this ment to work?

From Fb 1.5 onwards, *provided no Firebird environment variables are set AND no entry is present in the Registry*, you can theoretically run multiple instances of Firebird on Windows. This is because Fb was taught to look first in its root directory for its bits and pieces.

Both (all) can be services, provided each server instance is installed manually with its own service name. Running extra instances as applications is not a requirement. It's workaround used by people who don't know how or don't have privileges to create a service (sc.exe tool and/or its relatives).

>How can this be solved?

Without the cooperation of the vendor of the existing Firebird server installation, you can't solve it. You have no idea whether the other vendor's application depends on the presence of the Registry entry. Older software, especially any written using Borland/Codegear/Embarcadero tools, is prone to this limitation.

Then, of course, even with that solved, both of you and the other vendor will need to load-test vigorously to determine whether the server has sufficient resources to sustain multiple instances. In practical terms, especially if the existing host machine is serving databases from a 32-bit desktop OS (Win2k, XP, Vista, Win7), this may entail more effort and disappointment than installing your Firebird server on a different host machine from Day One.