usage:
group ls [-s] [-g <depth>] [-b|--brief] [-m|-l|--io] [<groups>] : list groups
<groups> : list <groups> only, where <groups> is a substring match and can be a comma seperated list
-s : silent mode
-g : geo output - aggregate group information along the instance geotree down to <depth>
-b : brief output
-m : monitoring key=value output format
-l : long output - list also file systems after each group
--io : print IO statistics for the group
--IO : print IO statistics for each filesystem
group rm <group-name> : remove group
group set <group-name> on|off : activate/deactivate group
=> when a group is (re-)enabled, the drain pull flag is recomputed for all filesystems within a group
=> when a group is (re-)disabled, the drain pull flag is removed from all members in the group