Restrictions for a z13 server

Restrictions associated with z Systems™ servers are:

  1. Functional limitations: Not all z13™ functions are available in every z/OS® release. See Table 1 and Table 2for a list of the z13 functions available in each z/OS release. Some functions have migration or exploitation considerations (see Actions you can take before you order a z13 server and Migration and exploitation considerations for z13 server functions. ) Many functions are enabled or disabled, based on the presence or absence of the required hardware and software. If you wish to position yourself to exploit any new z13 functions, you can install the software and hardware in either order; that is, there is no requirement to install either software or hardware first to exploit a specific function. However, because of outage windows and testing considerations, you might want to consider installing all the required software first, then upgrading the hardware and, finally, updating your customization to exploit the new functions.
  2. z13 servers in a sysplex:
    • A Parallel Sysplex® that contains a z13 server either for a z/OS image or a CF image can only contain other z13 servers or z196, z114, zEC12, or zBC12 servers.

      If you are running z/OS on any servers earlier than a z196 or z114 server, you cannot add a z13 server to that sysplex; that is, you will not be able to perform rolling IPLs to introduce a z13 server if you have any of the earlier servers as z/OS images or coupling facility images in the sysplex.

      The earlier servers in the sysplex must be upgraded to z196, z114, or later to have z13 servers supported in the sysplex. If you have any z/OS images or coupling facility images on an earlier server, and you intend to introduce a z13 server into that sysplex, you must migrate those images to a z196, z114, or later server before introducing the z13 server.

      If you are currently using ESCON CTCs for GRS ring configurations within a sysplex, consider using XCF signalling in a GRS ring configuration. XCF sysplex signalling is preferred instead of GRS CTC connections. Note that ESCON CTCs are not supported on a z13 server, and if you choose not to convert to XCF signalling, you will have to install toleration maintenance to enable GRS to use FICON® for GRS ring configurations. This support does not enhance the robustness of GRS-managed CTCs and the toleration must be installed across GRS complex. See Migrate to GRS-managed FICON CTCs.

    • InterSystem Channel 3 (ISC-3) and Integrated Cluster Bus 4 (ICB-4) Coupling Links are not supported on IBM z13™ CPC. Instead, the IBM® Integrated Coupling Adapter (ICA SR), introduced on the z13, is a two-port, short distance coupling fanout that utilizes a new coupling channel type: CS5. The ICA SR can only be used for coupling connectivity between z13 servers, and the ICA SR can only connect to another ICA SR. IBM recommends that you order ICA SR (#0172) on the z13 processors used in a Parallel Sysplex to help ensure coupling compatibility with future processor generations. You can also use 12x InfiniBand coupling links, which are designed to replace Integrated Cluster Bus 4 (ICB-4), and to complement 1x InfiniBand and ISC-3 on a z13 server. InfiniBand coupling can provide significantly improved service times compared to ISC-3s for distances up to 150 meters. You can read about coupling links in IBM System z® Connectivity Handbook (SG24-5444).
    • The z13 server cannot be connected to a Sysplex Timer (9037-002). The Server Time Protocol (STP) feature is the follow-on to the Sysplex Timer. STP is designed to allow multiple servers and coupling facilities to maintain time synchronization with each other without requiring a Sysplex Timer. STP is a hardware feature of the z13, zEC12, zBC12, z196, and z114. To implement STP, see the STP web site and the publications and other resources listed there. The STP web site is at http://www.ibm.com/systems/z/advantages/pso/stp.html .
      The STP design introduced a concept called Coordinated Timing Network (CTN). A CTN is a collection of servers and coupling facilities that are time-synchronized to a time value called Coordinated Server Time. A CTN can be configured in two ways:
      • STP-only CTN, which does not require a Sysplex Timer. A z13 must participate in an STP-only CTN.
      • Mixed-CTN (External Time Reference and STP), which does require a Sysplex Timer. zEC12 and zBC12 were the last servers to support mixed-CTN. z13 does not support connections to a Mixed-CTN. All servers in the network must be configured in STP-only mode. Consider migrating your servers that require time synchronization, such as to support a base or Parallel Sysplex(R), to the Server Time Protocol (STP).
  3. For a list of functions on the z13 server that are planned to be discontinued on future servers, see Accommodate functions for the z13 server to be discontinued on future servers
  4. Unsupported hardware features: The following hardware features cannot be ordered and cannot be carried forward from an upgrade on an earlier server to the z13 server.
    • HCA2-O
    • HCA2-O LR
    • ISC-3 links
    • CHPID type OSN (OSA-Express for NCP) is not supported on the OSA-Express5S GbE LX feature
    • Crypto Express3 (#0864)
    • Start of changeCrypto Express4S (#0865)End of change
    • STP Mixed CTN. The zEC12 and zBC12 were the last z Systems servers to support connections to an STP Mixed CTN. This also includes the Sysplex Timer (9037). Starting with z13, servers that require Time synchronization, such as to support a base or Parallel Sysplex, will require Server Time Protocol (STP) and all servers in that network must be configured in STP-only mode.
    • IBM System z Application Assist Processor (zAAP). IBM continues to support running zAAP workloads on IBM System z Integrated Information Processors (zIIPs). IBM has removed the restriction preventing zAAP-eligible workloads from running on zIIPs when a zAAP is installed on the CEC. This was intended to help facilitate migration and testing of zAAP workloads on zIIPs. With a z13, one CP must be installed with the installation of any zIIPs or prior to the installation of any zIIPs. The total number of zIIPs purchased cannot exceed twice the number of CPs purchased. However, for upgrades from zEC12s with zAAPs, conversions from zAAPs may increase this ratio to 4:1.
    Carry forward hardware features: The following hardware features are not orderable on z13 servers. If they are installed on your existing server at the time of an upgrade to a z13 server, they may be retained or carried forward.
    • HMC #0091
    • HCA2-C Fanout #0162
    • IFB-MP Daughter Card #0326
    • STI-A8 Mother Card #0327
    • Flash Express® #0402 and #0403
    • OSA-Express4S 1 GbE LX #0404
    • OSA-Express4S 1 GbE SX #0405
    • OSA-Express4S 10 GbE LR #0406
    • OSA-Express4S 10 GbE SR #0407
    • OSA-Express4S 1000BASE-T #0408
    • OSA-Express5S GbE LX #0413
    • OSA-Express5S GbE SX #0414
    • OSA-Express5S 10 GbE LR #0415
    • OSA-Express5S 10 GbE SR #0416
    • OSA-Express5S 1000BASE-T #0417
    • TKE workstation #0842
    • Addl smart cards #0884
    • TKE Smart Card Reader #0885
    • FICON Express8 10KM LX #3325
    • FICON Express8 SX #3326
    • FICON Express8S 10Km LX #0409
    • FICON Express8S SX #0410
    • 10GbE RoCE Express #0411
    • zEDC Express #0420
    • Fill and Drain Kit #3378
    • Universal Lift Tool/Ladder #3759

    Also, FICON Express8 will not be supported on future high-end z Systems servers as carry forward on an upgrade. The IBM z13 server will be the last z Systems server to offer ordering of FICON Express8S channel features. Enterprises that have 2GB device connectivity requirements must carry forward these channels.

    See Ensure you are running on supported servers and storage controllers for more information.

Parent topic: Migrate to an IBM z13 server