Given the following situation, I am wondering what advantages and
disadvantages there would be for creating more than one instance.

For testing, we want to have more than one 'version' of a database.
Probably there will be only a single database [structure, that is], although
there could be more.  Let's call this database CORE.  We'll could have a
single instance with, say, CORE_DEV1, CORE_DEV2, CORE_DEV3, etc.  (We'd also
have a separate production instance, on a separate machine, and just call
the database CORE.  Or maybe CORE_PROD.)

Anyway, for DEV the other alternative would be to have several instances,
each instance owning one of the DEV databases.  EG:
DB2INST1 with CORE_DEV1
DB2INST2 with CORE_DEV2
DB2INST3 with CORE_DEV3

And of course in this case we wouldn't need to have a suffix for each
database.  We could just call it CORE on each separate instance.

Of course clients connecting to the databases in the second case would have
to have aliases, such as, well, CORE_DEV1, CORE_DEV2, CORE_DEV3, etc.  :-)

When creating the dev databases (and there will probably be more than 3)
will it be easier to 'clone' another one if it has the same instance but a
different name or a different instance but the same name?  Or neither?  Does
having multiple instances make administrative tasks easier or more
difficult?  Or neither?  Anything else I should take in to consideration?

I am not the DBA, but the DBA is new to DB2 so I'd like to have some experts
weigh in on the matter.

Thanks!

Frank