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

mmchmgr Command

Name

mmchmgr - Assigns a File System Manager node.

Synopsis

mmchmgr Device [NodeName]

Description

The mmchmgr command assigns a File System Manager node.

Parameters

Device

The device name of the file system for which the File System Manager node is to be changed. File system names need not be fully qualified. fs0 is just as acceptable as /dev/fs0.

This must be the first parameter.

NodeName

The target node to be appointed as the new File System Manager.

If no NodeName is specified, the Configuration Manager selects the new File System Manager node.

The hostname or IP address used for a node must refer to the adapter port over which the GPFS daemons communicate. Alias interfaces are not allowed. Use the original address or a name that is resolved by the host command to that original address. You may specify a node using any of these forms:

Format	Example
Short hostname	k145n02
Long hostname	k145n02.kgn.ibm.com
GPFS cluster data server node number	16
Ethernet IP Address	9.119.19.102
Switch IP Address	9.1.13.216
Switch hostname	k145sw05

Options

NONE

Exit status

0

Successful completion.

1

A failure has occurred.

Security

You must have root authority to run the mmchmgr command.

In an SP environment:

1. 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.

2. You may issue the mmchmgr command from any node running GPFS or the CWS.
3. If you are executing the mmchmgr 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. 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 mmchmgr command from any node in the GPFS cluster.

Examples

Assume the File System Manager for the file system gpfs1 is currently node 15. To migrate the File System Manager responsibilities to node 16, enter:

mmchmgr gpfs1 k145n16

The system displays information similar to:

MMFS:  6027-628 Sending migrate request to current manager node 15 (k145n15)
MMFS:  6027-629 Node 15 (k145n15) resigned as manager for gpfs1
MMFS:  6027-630 Node 16 (k145n16) appointed as manager for gpfs1

The output shows the File System Manager's node number and name in parenthesis as they are registered in the GPFS cluster data.

See also

mmlsmgr Command

Location

/usr/lpp/mmfs/bin