Postgres HA using Shared Disk Solution

Hello All,

I have been researching for possible HA solutions for postgres. I find
shared disk solution (either using Linux-HA or RHCS) to be a very good
solution. Especially for us, because our databases are big and they do a
lot of IO so we deploy a lot of disks.

However, research on the internet shows that a shared disk solution is not
very commonly deployed when it comes to postgres. People mostly go for
Streaming Replication/Warm/Hot-Standby which to me are more like DR
solutions.

Is my research correct or that is not so? for e.g. this was the only post
that I came across, and that too as old as 2012:
https://www.postgresql.org/message-id/4F68E989.7080101%40d2.com

Given our IO requirement, if we go for Streaming Replication instead, then
our storage needs double and that increases the cost.

Can someone confirm, if shared disk clustering is fairly common or no in
the postgres world? If no, why is it so - can somebody enlighten me pls.

Many Thanks