Selecting bus-level or IOP-level partitioning

 

Depending on your needs, there can be advantages to partitioning your I/O resources in different ways.

 

Bus-level partitioning

With bus-level I/O partitioning, you dedicate an I/O bus and all resources on the bus to the same partition. A partition using the bus-level configuration, all I/O resources (included the alternate IPL device, console, and electronic customer support device) are dedicated and no resources are dynamically switched into or out of the partition. On a server that has partitions at the bus level, all buses are owned dedicated by their respected partitions and no devices are switched.

Bus-level logical partitions allow for:

• Better problem isolation and therefore higher availability.

• Better performance.

• Simplified hardware management.

 

IOP-level partitioning

When you partition a bus at the IOP level, you share the bus and divide up the I/O resources by IOP. This type of logical partitions allows for:

• Greater flexibility with partition I/O subsystems.

• Potential cost reduction by eliminating some expansion units that you may need to support additional buses.

• Optimization of hardware resources to avoid server limits such as 19 buses per server (only on AS/400e™ models).

• The ability to dynamically switch an IOP from one logical partition to another without the need to restart the server.

• Simplified configuration planning since hardware movement is not necessary.

Additionally, it is possible to configure a partition to utilize both dedicated buses and dedicated IOPs on shared buses.

 

Parent topic:

Hardware requirements for logical partitions

Related concepts
Dynamically switching IOPs between partitions Choosing dedicated or switchable IOP and devices for logical partitions