6/17/09

AIX df command

df Command

Purpose

Reports information about space on file systems. This document describes the AIX df command as well as the System V version of df.

Syntax

df [ [ -P ] | [ -I | -M | -i | -t | -v ] ] [ -k ] [ -m ] [ -g ] [ -s ] [FileSystem ... | File... ]

Description

The df command displays information about total space and available space on a file system. The FileSystem parameter specifies the name of the device on which the file system resides, the directory on which the file system is mounted, or the relative path name of a file system. The File parameter specifies a file or a directory that is not a mount point. If the File parameter is specified, the df command displays information for the file system on which the file or directory resides. If you do not specify the FileSystem or File parameter, the df command displays information for all currently mounted file systems. File system statistics are displayed in units of 512-byte blocks by default.

The df command gets file system space statistics from the statfs system call. However, specifying the -s flag gets the statistics from the virtual file system (VFS) specific file system helper. If you do not specify arguments with the -s flag and the helper fails to get the statistics, the statfs system call statistics are used. Under certain exceptional conditions, such as when a file system is being modified while the df command is running, the statistics displayed by the df command might not be accurate.

Note:
Some remote file systems, such as the Network File System (NFS), do not provide all the information that the df command needs. The df command prints blanks for statistics that the server does not provide.

The df command does not fully support NFSv4 filesystems. Use the nfs4cl command to extract block and space information.

Flags

-g Displays statistics in units of GB blocks. The output values for the file system statistics would be in floating point numbers as value of each unit in bytes is significantly high.
-i Displays the number of used inodes and the percentage of inodes in use for the file system. This output is the default when the specified file system is mounted.
-I Displays information on the total number of blocks, the used space, the free space, the percentage of used space, and the mount point for the file system.
-k Displays statistics in units of 1024-byte blocks.
-m Displays statistics in units of MB blocks. The output values for the file system statistics would be in floating point numbers as value of each unit in bytes is significantly high.
-M Displays the mount point information for the file system in the second column.
-P Displays information on the file system in POSIX portable format.

When the -P flag is specified, the header line appears similar to:

Filesystem 512-blocks Used Available Capacity Mounted on\n

If the -k, -m or -g flag is specified in addition to the -P flag, the column heading 512-blocks is replaced by the respective units, depending on which of these flags is used with the -P flag.

File system statistics are displayed on one line in the following order:

FileSystem, TotalSpace, UsedSpace, FreeSpace, UsedPercentage, MountPoint

-s Displays statistics on unmounted JFS or Enhanced JFS file systems by the command line arguments. If there are no arguments specified, the -s flag has no effect. If the file systems specified by the argument are currently mounted or an argument is a file, the -s flag has no effect for that particular argument. To collect statistics on unmounted file systems, an argument must be a JFS or Enhanced JFS file system mount point or device, the file system must be listed in /etc/filesystems, and the user must have read access to the device.
-t Includes figures for total allocated space in the output.
-v Displays all information for the specified file system.

The values of the output parameters with the flags -m and -g would be rounded off to nearest second decimal digit. If all or any two of the -k, -m and -g flags are specified, the last one specified takes effect.

Exit Status

This command returns the following exit values:

0 Successful completion.
>0 An error occurred.

Examples

  1. To display information about all mounted file systems, enter:
    df

    If your system has the /, /usr, /site, and /usr/venus file systems mounted, the output from the df command resembles the following:

    Filesystem 512-blocks Free   %Used   Iused  %Iused  Mounted on
    /dev/hd0 19368 9976 48% 4714 5% /
    /dev/hd1 24212 4808 80% 5031 19% /usr
    /dev/hd2 9744 9352 4% 1900 4% /site
    /dev/hd3 3868 3856 0% 986 0% /usr/venus
  2. To display information about /test file system in 1024-byte blocks, enter:
    df -k /test
    Filesystem    1024 blocks    Free    %Used   Iused  %Iused  Mounted on
    /dev/lv11 16384 15824 4% 18 1% /tmp/ravi1
    This displays the file system statistics in 1024-byte disk blocks.
  3. To display information about /test file system in MB blocks, enter:
    df -m /test
    Filesystem    MB blocks    Free    %Used    Iused  %Iused  Mounted on
    /dev/lv11 16.00 15.46 4% 18 1% /tmp/ravi1
    This displays file system statistics in MB disk blocks rounded off to nearest 2nd decimal digit.
  4. To display information about the /test file system in GB blocks, enter:
    df -g /test
    Filesystem    GB blocks   Free     %Used    Iused  %Iused  Mounted on
    /dev/lv11 0.02 0.02 0% 18 1% /tmp/ravi1
    This displays file system statistics in GB disk blocks rounded off to nearest 2nd decimal digit.
  5. To display available space on the file system in which your current directory resides, enter:
    cd/
    df .

    The output from this command resembles the following:

    Device   512-blocks  free   %used   iused   %iused  Mounted on
    /dev/hd4 19368 9976 48% 4714 5% /

Files

/etc/filesystems Lists the known file systems and defines their characteristics.
/etc/vfs Contains descriptions of virtual file system types.

2 comments:

IPL said...

Please explain why free MB blocks are 15.46 vs total blocks 16.00 but % used is still showing 4%. Please also reply on (atiwari.sap@gmail.com)

df -m /testFilesystem MB blocks Free %Used Iused %Iused Mounted on/dev/lv11 16.00 15.46 4% 18 1% /tmp/ravi1

భాస్కర్ రామరాజు said...

Please read the following in point 3.

This displays file system statistics in MB disk blocks rounded off to nearest 2nd decimal digit.