The gpperfmon Database - diskspace_* - 《Greenplum Database v6.23 Documentation》

The diskspace_* tables store diskspace metrics.

diskspace_now is an external table whose data files are stored in $MASTER_DATA_DIRECTORY/gpperfmon/data. Current diskspace metrics are stored in database_now during the period between data collection from the gpperfmon agents and automatic commitment to the diskspace_history table.
diskspace_tail is an external table whose data files are stored in $MASTER_DATA_DIRECTORY/gpperfmon/data. This is a transitional table for diskspace metrics that have been cleared from diskspace_now but has not yet been committed to diskspace_history. It typically only contains a few minutes worth of data.
diskspace_history is a regular table that stores historical diskspace metrics. It is pre-partitioned into monthly partitions. Partitions are automatically added in two month increments as needed.

Column	Type	Description
`ctime`	timestamp(0) without time zone	Time of diskspace measurement.
`hostname`	varchar(64)	The hostname associated with the diskspace measurement.
`Filesystem`	text	Name of the filesystem for the diskspace measurement.
`total_bytes`	bigint	Total bytes in the file system.
`bytes_used`	bigint	Total bytes used in the file system.
`bytes_available`	bigint	Total bytes available in file system.

Parent topic: The gpperfmon Database