Subject Re: [firebird-support] Clustering
Author Ann W. Harrison
At 09:46 AM 11/14/2004, Bert_Herngreen wrote:

>I'm trying to find out how I can create a cluster for testing
>purposes. Until now I didn't find information for firebird on this.

There is no information to find. InterBase, the precursor to Firebird
ran - probably still runs - on VAX Clusters. Other than that, there is
no cluster support for Firebird.

>I read about openmosix and doubt if this can
>be used to let the 2 computers in the cluster talk to each other and
>share load.

It won't. Firebird runs in two modes: classic and Superserver.

In Superserver and embedded which uses the same architecture, a single
process handles all data activity. Swapping that process back and
forth between processors will achieve no parallelism and incur the
cost of the swap. In short, a big lose.

In Classic mode, many separate processes access the database
simultaneously. That is the mode that worked on VAX clusters.
However the processes must coordinate their read/write activities.
VAX clusters include a distributed lock manager which provides that
coordination. Firebird uses a shared memory lock manager, similar
in design to the VAX lock manager. It works on SMP because the
processors share memory. Without shared memory, it won't work.

The OpenDLM project may provide a solution and should be studied.