CFS enables page-level compression in Shardman. Compression can only be enabled for separate tablespaces. To compress a tablespace, you need to enable the compression option when creating this tablespace. For example:

CREATE TABLESPACE data LOCATION '/mnt/data-{rgid}' WITH (global, compression='zlib');

Now you can create tables and indexes in this tablespace or move existing table or index to it.

CREATE TABLE pgbench_branches (
       bid integer NOT NULL PRIMARY KEY USING INDEX TABLESPACE data,
       bbalance integer,
       filler character(88)
)
WITH (distributed_by = 'bid') TABLESPACE data;

Complete CFS documentation can be found here.