We’re planning to upgrade our existing VPostgres ver 9.1.3 to Community Postgres ver 9.3. Besides upgrading the database, we’re also going to move some databases to a new server, and need to make the downtime as minimum.
I’m currently planning for the migration strategy, and need input for below questions:
1.Is pg_upgrade works for doing the above upgrade?
VMware may have changed to on disk format a bit so pg_upgrade may not work. You'll need to check with them.
2.For setting up Streaming Replication, do Primary and Standby must be on the same version? I think it has tobe, but want to get confirmation from community.
Yes, streaming replication needs to be the same version as well as the same type of OS. For example, you can replicate from 32bit Windows to 64bit Linux.
3.Does SLONY support the different versions of PG between Primary & Standby? OR any other solution?
Yes
4.What are the ways to minimize the downtime during migration?