Offline Tablespaces and Partial Restore

I'm evaluating the use of PostgreSQL to our production mission-critical
application that currently runs on SQL Server 2012.

There is a huge partitioned table of archived information that is
occasionally queried (+5TB) and are not required to be 24/7 online. An
eventual failure on the filesystem that stores these tables must not
compromise the whole cluster.

Another concern is on an eventual restore of the database, as I havent
found a way to start the cluster without some of its tablespaces.

I've tried to put the data on another database but it didn't help as
tablespaces are required cluster-wide on startup.

Is there a way to take these tablespaces offline so I could do some
maintenace work or startup the database with the archived data offline?

Thanks in advance,
Pedro Ivo