gpadmin=# \d gp_segment_configuration
Table "pg_catalog.gp_segment_configuration"
Column | Type | Modifiers
------------------+------------+-----------
dbid | smallint | not null
content | smallint | not null
role | "char" | not null
preferred_role | "char" | not null
mode | "char" | not null
status | "char" | not null
port | integer | not null
hostname | text |
address | text |
replication_port | integer |
san_mounts | int2vector |
Indexes:
"gp_segment_config_content_preferred_role_index" UNIQUE, btree (content, preferred_role), tablespace "pg_global"
"gp_segment_config_dbid_index" UNIQUE, btree (dbid), tablespace "pg_global"

Tablespace: "pg_global"

The gp_segment_configuration table contains information about mirroring and segment configuration.