Double calling of Web Service in Active-Active Clustering of BizTalk 2006 R2

Hi,

I have a
simple orchestration which is calling a web service and also have some sql db
calls.

About the
orchestration …

1. The
orchestration basically starts with a ‘RECEIVE’ shape which subscribes to
direct-bound messages from messagebox based on some filter
criteria.

2. It then
calls the web service, get the response and update to
DB.

3.
Orchestration ends.

We are
deploying this orchestration in a Active-Active cluster environment and we have
been noticing double calling of the web service within same orchestration
instance and also two orchestration instances started for same message resulting
also in two web service calls (just 2-3 seconds apart). We know this from our
log4net logs where we log our Orchestration instance ID and also our application
custom unique messageID plus timestamp. So it seems that there are 2 problems –
double calling of web service within a single orchestration instance and
double/duplicate subscription of a single message  from messagebox resulting in
extra web service call as well.

Does anyone
experience a similar behaviour in BizTalk 2006 R2 using Active-Active
clustering?

Note that
this behaviour does not happen in an Active-Passive cluster environment where we
try to run our orchestration.

Regards,

Aik Hwee