Integrated Facility for Linux (IFL)

You can purchase and install one or more IFL features exclusively for Linux® workloads (a single Linux image or z/VM® Version 7.1 and later with only Linux guests) with no effect on the model designation. Consequently, no additional IBM® operating system or middleware charges are incurred with the addition of this capacity unless that software is actually running in that additional capacity.

These features are ordered separately, and are distinguished at the hardware level from any general-purpose CPs, ICFs, or zIIPs. CPs, ICFs, IFLs, and zIIPs, are perceived by the system as multiple resource pools.

With this feature, Linux, or z/VM Version 7.1 or later with only Linux guests, runs on IFLs. These IFLs cannot be used to run other IBM operating systems such as z/OS®, 21CS VSEn, or z/TPF. Only logical partitions specified as either Linux-Only Mode or z/VM Mode in their Activation profiles can be allocated IFLs. IFLs can be allocated as either dedicated or shared. z/VM 7.1 and later can run in a logical partition that includes IFLs and can dispatch Linux guest virtual IFLs on the IFL logical processors. z/VM 7.1 and later can also simulate IFLs for Linux guests, dispatching virtual IFLs on general-purpose logical processors (CPs).

z/VM Mode allows z/VM users to configure all CPU types on a logical partition. z/VM 7.1 and later versions support this mode, which provides increased flexibility and simplifies systems management, by allowing z/VM to manage guests to perform the following tasks all in the same z/VM LP:

• Operate Linux on IFLs
• Operate 21CS VSEn, z/TPF, and z/OS on CPs
• Offload z/OS system software overhead, such as DB2® or Java workloads, on zIIPs

For more information, see Processor considerations for z/VM mode LPs.