IBM General Parallel File System for AIX: Administration and Programming Reference

mmdf Command

Name

mmdf - Queries available file space on a GPFS file system.

Synopsis

mmdf Device [-d | -F | -m ] [-q ]

Description

Use the mmdf command to display available file space on a GPFS file system.

For each disk in the GPFS file system, the mmdf command displays (by failure group):

• The size of the disk.
• The failure group of the disk.
• Whether the disk is used to hold data, metadata, or both.
• Available space in full blocks.
• Available space in fragments.

Displayed values are rounded down to a multiple of 1024 bytes. If the fragment size used by the file system is not a multiple of 1024 bytes, then the displayed values may be lower than the actual values. This can result in the display of a total value that exceeds the sum of the rounded values displayed for individual disks. The individual values are accurate if the fragment size is a multiple of 1024 bytes.

For the file system, the mmdf command displays:

• The total number of inodes and the number available.

The mmdf command may be run against a mounted or unmounted file system.

Note:

The command is an I/O intensive command and should be run when the system load is light.

Parameters

Device

The device name of the file system to be queried for available file space. File system names need not be fully qualified. fs0 is as acceptable as /dev/fs0.

This must be the first parameter.

Options

-d

List only disks that can hold data.

-F

List the number of inodes and how many of them are free.

-m

List only disks that can hold metadata.

-q

For quick access to the file space information, list the data collected from the most recent synchronization period.

Note:

With this flag the values recorded by mmdf are only synchronized at the last execution of the syncd daemon on the node where the command is issued.

The default is to list all disks.

Exit status

0

Successful completion.

1

A failure has occurred.

Security

In an SP environment:

• If you are a root user:
  • You may issue the mmdf command from any node running GPFS or the CWS.
  • Verify the authentication method set for SP security services:
    1. If your authentication method is set to compatibility, Kerberos authentication is required. Issue the k4init command.
    2. If your authentication method is set to DCE, dce_login authentication is required.
    3. If your authentication method is set to NONE/std, there must be an entry in the /etc/sysctl.mmcmd.acl file on every node in the nodeset for the root user at every other node in the nodeset.

    For further information, see the latest IBM Parallel System Support Programs for AIX: Administration Guide, IBM Parallel System Support Programs for AIX: Command and Technical Reference, and RS/6000: Planning Volume 2, Control Workstation and Software Environment manuals at www.rs6000.ibm.com/resource/aix_resource/sp_books/pssp. Search for information on sysctl.

• If you are executing the mmdf command from the CWS on a multi-partitioned system, the SP_NAME environment variable must be properly set. It is suggested that you use a separate window for each partition and set the environment variable accordingly. For further information, see the IBM Parallel System Support Programs for AIX: Administration Guide and search for understanding system partitioning.

In an HACMP environment:

1. If you are a root user, when using rcp and rsh for remote communication, a properly configured /.rhosts file must exist in the root user's home directory on each node in the GPFS cluster. If you have designated the use of a different remote communication program on either the mmcrcluster or the mmchcluster command, you must insure:
   1. Proper authorization is granted to all nodes in the GPFS cluster.
   2. The nodes in the GPFS cluster can communicate without the use of a password.
2. You may issue the mmdf command from any node in the GPFS cluster.

If you are a non-root user, you may only specify file systems that belong to the same nodeset as the node on which the mmdf command was issued.

Examples

To query all disks in the gpfssa file system, enter:

mmdf gpfssa

The system displays information similar to:

disk            disk size failure  holds    holds  free KB        free KB 
name            in KB     group    metadata data   in full blocks in fragments
--------------- --------- -------- -------- ------ -------------- ------------
gpfs33n11       2097152      -1      yes     yes   2049024 (98%)   1112 (0%)
gpfs35n11       2097152      -1      yes     yes   2049536 (98%)   1184 (0%)
gpfs37n11       2097152      -1      yes     yes   2047744 (98%)    470 (0%)
gpfs39n11       2097152      -1      yes     yes   2048512 (98%)    992 (0%)
                ---------                          ---------       ---------
(total)         8388608                            8194816 (98%)   3760 (0%)
 
Inode Information
-----------------
Total number of inodes: 10240
Total number of free inodes: 10169

See also

mmchfs Command

mmcrfs Command

mmdelfs Command

mmlsfs Command

Location

/usr/lpp/mmfs/bin