Changing your NSD configuration

Use the following steps to change the NSD configuration.

Once your NSDs have been created, you may change the configuration attributes as your system requirements change. For more information about creating NSDs, see the IBM Storage Scale: Concepts, Planning, and Installation Guide and the mmcrnsd command.

By issuing the mmchnsd command you can:

Specify up to eight servers for an NSD that does not have one.
Change the NSD server nodes specified in the server list.
Delete the server list. The disk must now be SAN-attached to all nodes in the cluster on which the file system will be mounted.

You must follow these rules when changing NSDs:

Identify the disks by the NSD names that were given to them by the mmcrnsd command.
Explicitly specify values for all NSD servers in the list, even if you are only changing one of the values.
Connect the NSD to the new nodes prior to issuing the mmchnsd command.
The mmchnsd command cannot change the DiskUsage or FailureGroup for an NSD. Use the mmchdisk command to change these attributes.
To move a disk from one storage pool to another, use the mmdeldisk and mmadddisk commands.
You cannot change the name of the NSD.

For example, to assign node k145n07 as an NSD server for disk gpfs47nsd:

Make sure that k145n07 is not already assigned to the server list by issuing the mmlsnsd command.

mmlsnsd -d "gpfs47nsd"

The system displays information similar to:

 File system   Disk name    NSD server nodes   
 ---------------------------------------------------------------
 fs1           gpfs47nsd    k145n09

Ensure that the disk is connected to the new node k145n07.
Issue the mmchnsd command:
```
mmchnsd "gpfs47nsd:k145n09,k145n07"
```

Verify the changes by issuing the mmlsnsd command:

mmlsnsd -d gpfs47nsd

The system displays information similar to:

  File system   Disk name    NSD servers
---------------------------------------------------------------------------
 fs2           gpfs47nsd    k145n09.ppd.pok.ibm.com,k145n07.ppd.pok.ibm.com