12.20 Disabling Clustering for a Pool

You can disable clustering for a pool by deleting the resource-related objects, and then re-creating the Pool and Volume objects on a desired node and unsharing the device. We strongly recommend that you delete the resource for a pool from the master node in the cluster.

The Cluster Options page of the Clusters plug-in for iManager provides a Delete option that automatically deletes the resource-related objects in eDirectory and updates the cluster information:

Cluster-named Pool object
Cluster-named Volume object for each of the pool’s volumes
Cluster Resource object for the pool
Virtual server for the cluster resource (NCS:NCP Server object)

Ensure that you offline the cluster resource before attempting to delete either the cluster resource or the clustered pool. For example, if you want to unshare a pool, you must offline the cluster resource for the pool before you mark the device as Not Shareable for Clustering. Then you can delete the eDirectory object for the cluster resource.

WARNING:If you attempt to delete a cluster resource without first offlining it, deletion errors occur, and the data associated with the clustered pool is not recoverable.

All resource configuration must happen from the master node. On the Cluster Options page for iManager, you are automatically connected to the Cluster object, which is associated with the master node. On the Storage > Pools page for iManager, connect to the Cluster object, not to the individual servers. Run NSSMU only on the master node.

This deletes the resource-related objects, but not the storage area they represent.

Use the following procedure to disable clustering for a pool:

If the resource is on a non-master node in the cluster, migrate it to the master node.

As the root user, open a terminal console, then enter
```
cluster migrate <resource_name> <master_node_name>
```
The master node must be in the resource’s preferred nodes list. To view or modify the list, see Section 10.10, Configuring Preferred Nodes and Node Failover Order for a Resource.
Use the cluster status command to check the resource status. If the resource is online or comatose, take it offline by using one of the following methods:
- Enter the following at the command prompt as the root user:
```
cluster offline <resource_name>
```
  Use the cluster status command to verify that the resource has a status of Offline before you continue.
- In iManager, go to Clusters > My Clusters, then select the cluster. On the Cluster Manager page, select the check box next to the cluster resource, then click Offline.
  
  Refresh the Cluster Manager page to verify that the resource has a status of Offline before you continue.
In iManager, use the Clusters plug-in to delete the cluster resource.
1. Select Clusters > My Clusters, then select the cluster.
2. Select the Cluster Options tab.
3. Select the check box next to the resource, then click Delete.
4. When you are prompted to confirm the deletion, click OK to continue, or click Cancel to abort the deletion.
5. In the Tree View in iManager, browse to verify that the Cluster Resource object and related objects were removed from eDirectory.
  
  If necessary, you can manually delete the objects. In iManager, go to Directory Administration > Delete Objects, select the objects, then click OK.
Use the Update eDirectory function to re-create Storage objects for the pool and its volumes.
1. In iManager, select Storage > Pools, then select the node where you want the pool to reside as a locally available pool.
2. Select the pool, then click Activate.
3. Select the pool, then click Update eDirectory.
  
  This creates a Pool object in eDirectory with a name format of <server_name>_<pool_name>_POOL.
4. Select Storage > Volumes. The server should still be selected.
5. Select the volume, then click Mount.
6. Select the volume, then click Update eDirectory.
  
  This creates a Volume object in eDirectory with a name format of <server_name>_<volume_name>.
7. Repeat Step 4.e through Step 4.f for each volume in the pool.
8. In the Tree View in iManager, browse to verify that the server-named Pool object and Volume object were created.
  
  For example, the following Tree View shows the Pool object avalon_POOLD_POOL and the Volume object avalon_VOLD were created for server avalon.
Unshare the devices that contribute space to the pool, then use a third-party SAN management tool to assign the devices to only the desired server.
1. In iManager, go to Storage > Devices, then select the desired server (the one you specified in Step 4).
2. Select the device.
3. Deselect the Shareable for Clustering check box, then click Apply.
  
  Unsharing a device fails if the device contains a cluster-enabled pool or split-brain detector (SBD) partition. This is unlikely to be an issue if you used a dedicated device (or devices) for the pool where you have disabled clustering.
4. Repeat these steps for each device that contributes space to the pool.
5. Use a third-party SAN management tool to assign the devices to only the desired server.
Provide the node’s IP address to users who access volumes on the non-clustered pool.