SAN Volume Controller Technical Tips
Debi Riedel
Technologies Resource Manager
Datatrend Technologies

Here's a set of handy tips when working with the SAN Volume Controller:

Tip 1 - Updated procedure for performing a Cluster shutdown (stopcluster).

Before performing a cluster shutdown, check the state of all FlashCopy mappings, ensuring that none are in the ‘preparing’ or ‘prepared’ state.

If any mappings are in these states, perform the following steps, prior to shutting down the cluster.

• For mappings in the preparing state:
  Wait until the mapping has reached either the ‘prepared’ or ‘stopped’ state, and then perform the instructions for mappings in the prepared state.

• For mappings in the prepared state:
  Prepared state mappings need to be stopped. For mappings which are not part of the default consistency group (Group 0), execute the svctask stopfcconsistgrp command.

• For mapping in the default consistency group:
  Execute the svctask stopfcmap command.
  Note: each mapping in Group 0 must be stopped individually.

Tip 2 – What is meant when a controller is reported in a 'degraded' status.    

A controller is classified as ‘degraded‘ when the number of fabric logins to the controller is less than the maximum previously recorded for any given SVC cluster node and controller port combination.

The controller ‘degraded’ status is not related to the state of the MDisks that are associated with the controller.

It should be noted that individual MDisks can also be reported as in a ‘degraded’ status. The degraded MDisk will not cause the associated cluster to be placed into a degraded status.

Execute the svcinfo lscontroller <controller_name> command to obtain the controller detail view.

Tip 3 – When using the SAN Volume Controller Console to set the SNMP Trap destination IP address, a situation may occur where the address seems to be set, but the SAN Volume Controller does not send any SNMP Traps to the master console (IBM Director).

You can use the Command-Line function to set the SNMP Trap destination IP Address.

• log-on as service
• use putty to access the Command interface to the Cluster
• Enter the command:
  svcservicetask setevent -snmptrap all -snmpip < IP address of the master console> -community public

I hope you find these tips useful. Please contact me at debi.riedel@datatrend.com with any questions.  Or feel free to ask for technical advice on various IT topics by emailing techtips@datatrend.com.

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