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.
For the most part, I am completely on the fence about deciding either
way. What does the postgres community recommend in this situation? All
docs and books that I read seem to suggest that a postgres instance
manages databases (plural!) and normally there would be only one
postgres instance running per host.
I am also interested in the best way forward with failover and high
availability.
Looking forward to comments,
Sam