Planning for nondisruptive upgrades Guidelines to avoid disruptive upgrades Online permanent upgrades, On/Off CoD, CBU, and CPE can be used to upgrade  concurrently a z14 ZR1 server. However, certain situations require a disruptive task to enable  capacity that was recently added to the system. Some of these situations can be avoided if  planning is done. Planning ahead is a key factor for nondisruptive upgrades. Disruptive upgrades are performed for the following reasons:  You can minimize the need for these outages by carefully planning and reviewing “Guidelines  to avoid disruptive upgrades” on page 324. GLYPH<SM590000> LPAR memory upgrades when reserved storage was not previously defined are disruptive  to image upgrades. z/OS and z/VM support this function. GLYPH<SM590000> Upgrading from one CPC drawer feature to another (for example, from a Max4 to a  Max12) by adding one or more PU SCMs is disruptive. Reasons for such an upgrade  might be when: – More PU capacity is required – More physical memory is required – More PCIe Fanouts are required to install an ICA SR card or extra PCIe+ drawer GLYPH<SM590000> Any installation of physical memory, also within the same CPC drawer feature, is  disruptive. GLYPH<SM590000> An I/O upgrade when the operating system cannot use the dynamic I/O configuration  function is disruptive to that partition. Linux, z/VSE, z/TPF, and CFCC do not support  dynamic I/O configuration. GLYPH<SM590000> By using an SE function that is called Logical Processor add (which is under Operational  Customization tasks), CPs and zIIPs can be added concurrently to a running partition. The  CP and zIIP and initial or reserved number of processors can be changed dynamically.  GLYPH<SM590000> The operating system that runs in the targeted LPAR must support the dynamic addition of  resources and to configure processors online. The total number of defined and reserved  CPs cannot exceed the number of CPs that are supported by the operating system. z/OS  V1R13 with PTFs supports up to 100 processors. z/OS V2R1 and later supports 256 PUs  per z/OS LPAR in non-SMT mode and 128 PUs per z/OS LPAR in SMT mode. For both,  the PU total is the sum of CPs and zIIPs .  z/VM supports up to 64 processors. GLYPH<SM590000> Configure reserved storage to LPARs. GLYPH<SM590000> Consider the plan-ahead memory option. Based on the reasons for disruptive upgrades (see “Planning for nondisruptive upgrades” on  page 324), you can use the following guidelines to avoid or at least minimize these situations,  which increases the chances for nondisruptive upgrades: Configuring reserved storage for all LPARs before their activation enables them to be  nondisruptively upgraded. The operating system that is running in the LPAR must  configure memory online. The amount of reserved storage can be above the CPC drawer  threshold limit, even if no other CPC drawer is already installed. With z14 servers, the  current partition storage limit is 4 TB for z/OS V2.3, V2.2, and V2.1. z/VM 6.4 supports  2 TB memory partitions.  Use a convenient entry point for memory capacity, and select memory options that allow  future upgrades within the memory cards that are installed on the CPC drawer. For more  information about the offering, see 2.5.6, “Preplanned memory” on page 45. 324  IBM 14 Model ZR1 Technical Guide