Chapter 5. Red Hat OpenShift installation planning and considerations 87
/SM590000The following options are available for setting up virtual storage on your VIO servers:
– Shared Storage Pool (SSP)
These pools allow a single physical volume on any supported storage controller to be 
shared across a cluster of Virtual I/O Servers. Those Virtual I/O Servers share 
accesses to aggregated physical volumes and divide that aggregated volume into 
storage volumes instead of interacting with external storage controllers or fabric 
switches. 
A cluster consists of up to 16 Virtual I/O Servers with a shared storage pool that 
provides distributed storage access to the Virtual I/O Servers in the cluster. Each 
cluster requires one physical volume for the repository physical volume and at least 
one physical volume for the storage pool physical volume. The shared storage pool can 
be accessed by all the Virtual I/O Servers in the cluster. All the Virtual I/O Servers 
within a cluster must have access to all the physical volumes in a shared storage pool.
– Virtual SCSI (vSCSI) adapters
These adapters provide one logical partition with the ability to use storage I/O (disk, 
CD, and tape) that is owned by the Virtual I/O Server partition. Virtual SCSI is based on 
a client and server relationship; the Virtual I/O Server owns the physical resources and 
has one Virtual SCSI server adapter that communicates with a logical partition Virtual 
SCSI client adapter.
– N_Port ID Virtualization (NPIV)
The NPIV allows a single physical HBA to register multiple virtual WWPNs. With NPIV, 
you can configure the managed system so that multiple partitions can access 
independent physical storage through the same physical Fibre Channel adapter. 
Each client partition is configured with four Virtual Fibre Channel adapters: two are 
mapped to Virtual Fibre Channel adapters on one VIOS and the other two are mapped 
to Virtual Fibre Channel adapters on the other VIOS. The client has WWPNs, four 
active and four inactive (used only during LPM operations). 
For client VMs to see same storage from all these ports, zoning must be done on the 
SAN. Multi-path software on the client VM takes care of routing IO through passive 
path if the active path fails. The NPIV is recommended for production environments.