This section provides some information on the amount of usable space on the gateway (a 300 GB disk does not have 300 GB of usable space.)
Use the fdisk command to view the partition table. There are other unmounted partitions that do not show up in df output (perhaps /swap, for example). For example, the file system uses some of the disk partition for metadata. Metadata consists of entities like file names, file permissions, which parts of the partition belong to which files, and which parts of the partition are free. This might account for 2% of the partition. Space is also reserved for root and for the master boot record.
For example, on a sample gateway, the df -k command shows:
Filesystem Size Used Avail Use% Mounted on ----- /dev/mapper/vg_gateway-lv_root 12385456 5556096 6200216 48% /.
But the fdisk -l command shows:
Disk /dev/mapper/vg_gateway-lv_root: 12.9 GB, 12884901888 bytes.