Configuring Pacemaker constraints for Postgres on Shared Storage

Hi all,

I am configuring a 2-node Pacemaker cluster to manage a PostgreSQL
instance. The architecture relies on an external distributed storage array.
Node 1 and Node 2 both see the block device, but only the active node
should mount it and start PostgreSQL.

I want to ensure my Pacemaker colocation and ordering constraints are
mathematically airtight to prevent split-brain.

Currently, I am planning the following resource group/constraints:

1.

Virtual IP (IPaddr2)
2.

Filesystem Mount (Filesystem)
3.

PostgreSQL Service (pgsql)

My questions for the community:

-

Is it safer to group these resources together so they always migrate as
a single unit, or handle them via explicit colocation and order
constraints?
-

When using distributed storage, how do you handle the postgresql.conf
parameters like archive_command or tracking replication states when the
secondary node boots up using the exact same data directory bytes as the
primary?
-

If you have a working boilerplate XML or pcs command template for a
shared-storage Postgres setup, it would be incredibly helpful.

Appreciate any insights or pitfalls to avoid!

Thanks