IBM z13s, Technical Manual

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IBM z13s Technical Guide
Application preservation
If no spare PU is available,
application preservation
(z/OS only) is started. The state of the
failing processor is passed to another active processor that is used by the operating system.
Through operating system recovery services, the task is resumed successfully (in most
cases, without client intervention).
Dynamic SAP and IFP sparing and reassignment
Dynamic recovery
is provided during a failure of the SAP or IFP. If the SAP or IFP fails, and if
a spare PU is available, the spare PU is dynamically assigned as a new SAP or IFP. If no
spare PU is available, and more than one CP is characterized, a characterized CP is
reassigned as an SAP or IFP. In either case, client intervention is not required. This capability
eliminates an unplanned outage and allows a service action to be deferred to a more
convenient time.
3.5.11 Increased flexibility with z/VM mode partitions
z13s servers provide a capability for the definition of a z/VM mode LPAR that contains a mix
of processor types that includes CPs and specialty processors, such as IFLs, zIIPs, and ICFs.
z/VM V5R4 and later support this capability, which increases flexibility and simplifies systems
management. In a single LPAR, z/VM can perform these tasks:
򐂰 Manage guests that use Linux on z Systems on IFLs, and those that use z/VSE, or z/OS
on CPs
򐂰 Run designated z/OS workloads, such as Java and XML execution and parts of DB2
DRDA processing, on zIIPs
If the only operating system to run under z/VM is Linux, define a Linux only LPAR.
3.6 Memory design
This section describes various considerations of the z13s memory design.
3.6.1 Overview
The z13s memory design also provides flexibility, high availability, and upgrades:
򐂰 Concurrent memory upgrades (if the physically installed capacity is not yet reached): z13s
servers can have more memory physically installed than the initial available capacity.
Memory upgrades within the physically installed capacity can be done concurrently by LIC,
and no hardware changes are required. However, memory upgrades
cannot
be done
through CBU or On/Off CoD.
When the total capacity that is installed has more usable memory than required for a
configuration, the LIC Configuration Control (LICCC) determines how much memory is used
from each CPC drawer. The sum of the LICCC provided memory from each CPC drawer is
the amount that is available for use in the system.
Memory allocation
When system is activated by using a POR, PR/SM determines the total installed memory and
the customer enabled memory. Later in the process, during LPAR activation, PR/SM assigns
and allocates each partition memory according to its image profile.