adminMode configuration attribute

The adminMode attribute is set with the mmchconfig command and can have one of two values:

allToAll

Indicates that all nodes in the cluster can be used for running GPFS administration commands and that all nodes are able to execute remote commands on any other node in the cluster without the need of a password.

The major advantage of this mode of operation is that GPFS can automatically recover missing or corrupted configuration files in almost all circumstances. The major disadvantage is that all nodes in the cluster must have root level access to all other nodes.

central

Indicates that only a subset of the nodes will be used for running GPFS commands and that only those nodes will be able to execute remote commands on the rest of the nodes in the cluster without the need of a password.

The major advantage of this mode of administration is that the number of nodes that must have root level access to the rest of the nodes is limited and can be as low as one. The disadvantage is that GPFS may not be able to automatically recover from loss of certain configuration files. For example, if the SSL key files are not present on some of the nodes, the operator may have to intervene to recover the missing data. Similarly, it may be necessary to shut down GPFS when adding new quorum nodes. If an operator intervention is needed, you will see appropriate messages in the GPFS log or on the screen.

Note List:

1. If the GPFS cluster is configured to support Clustered NFS (CNFS), all CNFS member nodes must belong to the subset of nodes that are able to execute remote commands without the need of a password.
2. If a IBM Spectrum Protect™ server is used to back up the GPFS file system data, the nodes that are used as IBM Spectrum Protect clients must belong to the subset of nodes that are able to execute remote commands without the need of a password.
3. Windows GPFS clusters typically use central mode. allToAll mode requires that the GPFS Administrative service (mmwinserv) be configured to run as the special domain root account. For more information, see Procedure for installing GPFS on Windows nodes.

You can change the mode of operations at any time with the help of the mmchconfig command. For example, to switch the mode of administration from allToAll to central, issue:

mmchconfig adminMode=central