Dynamically managing physical I/O devices and slots on Linux

Learn how to dynamically add, remove, and move physical I/O devices and slots from one running logical partition to another using the Hardware Management Console (HMC). Learn how to make Linux® recognize the changes in the available resources.

This topic describes how to manage physical I/O devices and slots on Linux, limitations to this capability, and ways to work around those limitations.

Linux distributions Red Hat Enterprise Linux version 4 or SUSE Linux Enterprise Server 9 or later are required to dynamically move I/O devices and slots to or from a Linux logical partition.

If you add slots with adapters, the devices are automatically configured by Linux kernel modules (rpaphp and PCI Hotplug Core). However, after the devices have been added with the HMC, you must log in to the running Linux logical partition as root so you can set up those devices that have been added using the appropriate user space tools, such as the mount command or the ifup command.

If you remove adapters for storage devices, you must unmount the file systems on those devices before you remove the slots and adapters. Also, if you remove network adapters, you should shut down the network interfaces for those devices before removing the slots and adapters.

Logical partitions can have desired or required I/O devices or slots. When you specify that an I/O device or slot is desired (or shared), this means that the I/O device or slot is optional. When you specify that an I/O device or slot is required (or dedicated), then you cannot activate the logical partition if the I/O device or slot is unavailable or in use by another logical partition.

Note: If resources are moved dynamically, the configuration change is temporary and is not reflected in the partition profile. This means that all configuration changes will be lost the next time the partition profile is activated. To save your new partition configuration, modify the partition profile. For more information on changing the partition profile properties, see Changing partition profile properties using version 6 or earlier of the HMC.

To add physical I/O devices or slots to a running logical partition, follow these steps on the HMC:

In the navigation area, open Server and Partition.
Select Server Management.
In the contents area, open the server on which the logical partitions are located.
Open Partitions.
Right-click the logical partition and select Dynamic Logical Partitioning > Adapter Resources > Add.
In the Current area, open the unit with the physical I/O device or slot, open the planar with the physical I/O device or slot, and select the line corresponding to the physical I/O device or slot.
Select the I/O pool for the physical I/O device or slot (if any).
Click Advanced and adjust the settings there. You might need to increase the value in the Timeout setting field to allow enough time for the HMC to complete the operation. These settings relate to how the managed system adds the physical I/O device or slot dynamically. These settings are not retained after the change is completed.
Click OK.

Remove physical I/O devices or slots from a running logical partition

To remove physical I/O devices or slots from a running logical partition, follow these steps on the HMC:

In the navigation area, open Server and Partition.
Select Server Management.
In the contents area, open the server on which the logical partitions are located.
Open Partitions.
Right-click the logical partition and select Dynamic Logical Partitioning > Adapter Resources > Remove.
In the Current area, open the unit with the physical I/O device or slot, open the planar with the physical I/O device or slot, and select the line corresponding to the physical I/O device or slot.
Click Advanced and adjust the settings there. You might need to increase the value in the Timeout setting field to allow enough time for the HMC to complete the operation. These settings relate to how the managed system removes the physical I/O device or slot dynamically. These settings are not retained after the removal is completed.
Ensure that any devices attached to the I/O processor you want to remove are not busy. Unmount the file systems on any storage devices you are removing, and shut down any network interfaces on network devices you are removing.
Click OK.

Move physical I/O devices or slots

To move physical I/O devices or slots from one a running logical partition to another using the HMC, follow these steps:

In the navigation area, open Server and Partition.
Select Server Management.
In the contents area, open the server on which the logical partitions are located.
Open Partitions.
Right-click the logical partition and select Dynamic Logical Partitioning > Adapter Resources > Move.
In the Current area, open the unit with the physical I/O device or slot, open the planar with the physical I/O device or slot, and select the line corresponding to the physical I/O device or slot.
In Logical Partition, select the logical partition to which you want to move the physical I/O device or slot.
Click Advanced and adjust the settings there. You might need to increase the value in the Timeout setting field to allow enough time for the HMC to complete the operation. These settings relate to how the managed system moves the physical I/O device or slot dynamically. These settings are not retained after the move is completed.
Ensure that any devices attached to the I/O processor you want to remove are not busy. Unmount the file systems on any storage devices you are removing, and shut down any network interfaces on network devices you are removing.
Click OK.