>Howdy,
>I am looking for advice on migrating to postgres from another database
>system.
>
>Without going into too much detail, my company offers a software
>solution which we self host ourselves in our data center. We have gotten
>a green light from management to start using postgres as a free and
>cheaper database. Normally the application connects to a DB2 database.
>
>The current architecture has multiple DB2 databases installed on a
>single linux host (on top of vmware with 4 vcpus). Each DB2 instance
>runs as a different local linux user and only manages one database.
>Normally there are less than 5 DB2 instances per host.
>
>My question is, if I am going to replace DB2 as the database with
>Postgres, should I keep to this architecture of each customer
>application gets their own database instance? What I was thinking would
>be much more simpler would be to have multiple databases under one
>postgres instance (which is how most linux distros install postgres
>anyway). Having multiple databases under one instance seems to be a much
>easier way. Of course then the issue becomes if there is an issue with
>this single instance, multiple customers will be affected.
Hello,
Another possible approach is to have only one database
but one schema per user.
This allows e.g. to share resources like stored procedures upon the public schema
or to run queries against all customers as super user.
The caveat being that users are less isolated (everybody can read the catalog).
regards,
Marc Mamin