Error encountered while creating and using NSD disks

Use mmcrnsd command to prepare NSD disks. While preparing the NSD disks, there are several errors conditions encountered.

GPFS requires that disk devices be prepared as NSDs. This is done using the mmcrnsd command. The input to the mmcrnsd command is given in the form of disk stanzas. For a complete explanation of disk stanzas, see following topics:

For disks that are SAN-attached to all nodes in the cluster, device=DiskName should refer to the disk device name in /dev on the node where the mmcrnsd command is issued. If a server list is specified, device=DiskName must refer to the name of the disk on the first server node. The same disk can have different local names on different nodes.

When you specify an NSD server node, that node performs all disk I/O operations on behalf of nodes in the cluster that do not have connectivity to the disk. You can also specify up to eight additional NSD server nodes. These additional NSD servers will become active if the first NSD server node fails or is unavailable.

When the mmcrnsd command encounters an error condition, one of these messages is displayed:

6027-2108: Error found while processing stanza

6027-1636: Error found while checking disk descriptor descriptor

Usually, this message is preceded by one or more messages describing the error more specifically.

Another possible error from mmcrnsd is:

6027-2109: Failed while processing disk stanza on node nodeName.

6027-1661: Failed while processing disk descriptor descriptor on node nodeName.

One of these errors can occur if an NSD server node does not have read and write access to the disk. The NSD server node needs to write an NSD volume ID to the raw disk. If an additional NSD server node is specified, that NSD server node will scan its disks to find this NSD volume ID string. If the disk is SAN-attached to all nodes in the cluster, the NSD volume ID is written to the disk by the node on which the mmcrnsd command is running.