* Warren Little <warren.little at meridiascapital.com> [070321 16:23]:
>    Hello,
>    I need to get data migrated from a pg8.1 cluster to a pg8.2 cluster and
>    was wondering how well slony will accomplish this task.
>    The database size is about 250GB, so doing a dump and restore will take
>    longer than the maintenance window for system downtime.
>    I have read several posts on the postgres mailing lists that people
>    recommend using slony to do major version upgrades, so I thought to give
>    it a try.

It works in practice well. Furthermore you should consider it, or
something else to have a hotstandby backup of your database anyway.
Another IMHO important benefit is that such a cluster, even if unused
by the application, can be used to do pg_dump style backups without
putting disc IO pressure onto the master server.

>    One of the concerns I have is regarding the limitation that slony does not
>    support large objects, is this referring to the postgres LargeObject type?
This refers to the pseudo file large objects, not to anything stored
directly in tables.
>    ie are bytea fields of significant size replicated?
yes.
>    Also, is there a guide to configuring Slony-I on an active system, or is
>    the procedure the same (aside for the standard "backup all data before you
>    begin") 
Well, if it's a mission critical system, you should consider hiring a
consultant to walk you through in detail or do it himself. It's not
exactly a lengthy procedure, so it shouldn't cost you to much.

OTOH, the procedure is basically as documented. Personally, I've found
that the documentation somehow manages to be correct and complete, and
yet it makes one sweet the first times one does some operation ;)

Andreas