ALTER DISKGROUP { diskgroup_name { add_disk_clause | drop_disk_clause } [, { add_disk_clause | drop_disk_clause } ]... | resize_disk_clauses } [ rebalance_diskgroup_clause ] | {rebalance_diskgroup_clause | check_diskgroup_clause | diskgroup_template_clauses | diskgroup_directory_clauses | diskgroup_alias_clauses | drop_diskgroup_file_clause } | { diskgroup_name [, diskgroup_name ]... | ALL } { undrop_disk_clause | diskgroup_availability } }