When a disk partition is nearly full, the df command shows zero available disk space and 100% of disk used. For example:
[[email protected] admin]# df -h /tftpboot
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/d1vg-lv3 201G 192G 0 100% /tftpboot
The file system on the CPM marks 5% of the available disk capacity as reserved. If less than 5% is free, using the remaining reserved space requires root privileges. Any non-privileged users and processes are unable to write new data to the partition.
On a large partition like in this example (201GB), the reserved 5% represent about 10GB of disk capacity. Such partition with more than 191GB utilized space will be shown as 100% full because 100% of the non-reserved space is used.
To restore disk write access for non-privileged users and processes, it is necessary to identify files that can be deleted and free up the disk space. Once the 5% threshold is crossed, the Use percentage drops bellow 100%:
[[email protected] admin]# df -h /tftpboot
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/d1vg-lv3 201G 188G 2.5G 99% /tftpboot