df - Display the amount of free space in the file system


df[-kPStv][file ...]


df shows the amount of free space that is left on a file system. Space can have the following values:
Space Used
Total amount of space that is allocated to existing files in the file system.
Space Free
Total amount of space available in file system for the creation of new files by unprivileged users.
Space Reserved
Space reserved by the system, which is not normally available to a user.
Total Space
Includes space used, space free, and space reserved.
df measures space in units of 512-byte disk sectors. You can specify a particular file system by naming any file name on that file system. If you do not give an argument, df reports space for all mounted file systems known to the system, in the following format:
  • File system root.
  • File system name.
  • Space available and total space.

    The total space reported is the space in the already allocated extents (primary and any already allocated secondary extents) of the data set that holds this file system. Therefore, the total space might increase as new extents are allocated.

  • Number of free files (inodes).

    This number is only meaningful for file systems created using DFSMS 1.3.0 and later. For file systems created with earlier versions of DFSMS, this number is always 4 294 967 295.

  • File system status.
Tip: For zFS file systems, the df command might not provide sufficient information to indicate whether a file system is running out of space. For complete information about zFS space usage, use the zfsadm aggrinfo -long command. See z/OS Distributed File Service zFS Administration for more information.


Uses 1024-byte (1 KB) units instead of the default 512-byte units when reporting space information.
Lists complete information about space used, in the following order:
  • File system name.
  • Total space.
  • Space used.
  • Space free.
  • Percentage of space used.
  • File system root.
Display SMF accounting fields.
Display total allocated file slots, in addition to the total number of free files that are already displayed.
Lists more detailed information about the file system status.
  • File system root.
  • File system name.
  • Space available and total space.
  • Number of free files (inode).
  • File system status.
  • File system type, mode bits, and device number.
  • File system mount parm data.
  • File system mount tag value.
  • Whether ACLs are supported by the security product and file system.
  • Aggregate name, if one exists.
  • File system ID issuing a quiesce request.
  • User name and effective UID of the user who mounted the file system, if it was a nonprivileged user mount.
For systems in a shared file system environment, the following additional fields are displayed:
  • File system ID (owner/mounted file system server)
  • File system automove status (yes-Y, no-N, include-I, exclude-E or unmount-U)
  • File system client status
  • System list and include/exclude indicator, if the system list exists
  • PFS normal status, if one exists
  • PFS exception status, if one exists

Usage notes

  1. Some information might not be available if the underlying physical file system (PFS) could not be provided because of a heterogeneous environment or Protocol limitation.
    Example: In the following example, the df command that displays an NFS Version 2 mount point shows 0 under the Files field.
    df /fsdirs2
    Mounted on     Filesystem      Avail/Total         Files       Status
    /fsdirs2       (fs2)           8065166/8112960      0          Available


If you issue a df -v on a file system whose owner is participating in shared file system, status information such as the following example is displayed:
Mounted on     Filesystem         Avail/Total     Files       Status
/u/billyjc    (OMVS.ZFS.BILLYJC)  365824/3165120  4294924769  Available
ZFS, Read/Write, Device: 17,ACLS=Y, No SUID, Exported, No Security
File System owner: AQFT  Automove=E  Client=N  
System List (Exclude):  sysname1   sysname2   ....  sysnameN	  
Quiesce Owner    : AQTS    Quiesce Jobname : MEGA    Quiesce PID: 16777321 
Filetag : T=on    codeset=ISO8859-1
Aggregate Name:  POSIX.ZFS.ETC


df uses the following localization environment variables:
  • LANG
  • LC_ALL

See Localization for more information.

Exit values

Successful completion.
Failure due to any of the following reasons:
  • Inability to access filename.
  • Inability to access device.
  • device is not a device.
Incorrect command-line option.


POSIX.2 User Portability Extension, X/Open Portability Guide, UNIX systems.

Related information

du, ls