Monitoring and Managing Disk Space Usage
This section looks at the tools available to monitor and track disk space usage. It then goes on to discuss ways of approaching a perennial administrative challenge: getting users to reduce their disk use.
Where Did It All Go?
df -k command produces a report that describes all the
filesystems, their total capacities, and the amount of free space
available on each one (reporting sizes in KB). Here is the output from
a Linux system:
File system Kbytes used avail capacity Mounted on /dev/sd0a 7608 6369 478 93% / /dev/sd0g 49155 45224 0 102% /corp
This output reports the status of two filesystems: /dev/sd0a, the root disk, and /dev/sd0g, the disk mounted at corp (containing all files and subdirectories underneath /corp). Each line of the report shows the filesystem’s name, the total number of kilobytes on the disk, the number of kilobytes in use, the number of kilobytes available, and the percentage of the filesystem’s storage that is in use. It is evident that both filesystems are heavily used. In fact, the /corp filesystem appears to be overfull.
As we’ve noted earlier, the operating system generally holds back some amount of space in each filesystem, allocatable only by the superuser (usually 10%, although Linux uses 5% by default). A filesystem may appear to use over 100% of the available space when it has tapped into this reserve.
du -k command reports the amount of disk space used by all files and subdirectories underneath one or ...