Ensure that enough real memory is installed
Description
For z/OS V2R3 with the IBM z14™ (z14) server, a minimum of 8 GB of real memory is required to IPL. When running as a z/VM guest or on an IBM Z® Personal Development Tool (zPDT), a minimum of 2 GB is required for z/OS V2R3.
If you attempt to IPL z/OS V2R3 on a z14 with less than the minimum amount of
real memory, z/OS issues the following warning message (a WTOR) during IPL:
IAR057D LESS THAN 8 GB OF REAL STORAGE IMPACTS SYSTEM AVAILABILITY - ADD STORAGE OR
REPLY C TO CONTINUE Continuing with less than the minimum amount of real memory might impact the availability of your system. If you attempt to IPL z/OS V2R3 on an earlier IBM server, no warning message is issued.
To help you with migrating from z/OS V2R1 or V2R2, IBM provides a new health check, IBMRSM,RSM_Minimum_Real, which issues a warning for a system that is configured with less than 8 GB of real memory.
This table provides more details about the migration action. Use this information to plan your
changes to the system.
| Element or feature: | Multiple |
|---|---|
| When change was introduced: | z/OS V2R3. |
| Applies to migration from: | z/OS V2R2 and z/OS V2R1. |
| Timing: | Before the first IPL of z/OS V2R3. |
| Is the migration action required? | Yes. |
| Target system hardware requirements: | IBM z14 server. |
| Target system software requirements: | None. |
| Other system (coexistence or fallback) requirements: | None. |
| Restrictions: | None. |
| System impacts: | If the system detects that it is running on a z14 server, and less than 8 GB of real memory is configured, the system issues warning message IAR057D (a WTOR) during IPL. |
| Related IBM® Health Checker for z/OS® check: | Use IBM Health Checker for z/OS check, IBMRSM,RSM_Minimum_Real, which determines whether the minimum memory requirements are met. |
Steps to take
For a z/OS V2R3 system that you plan to run on a z14 server, follow these steps:
- For a system that is running as a z/VM guest, ensure that the server has a minimum of 2 GB of real memory.
- For a system that is running on IBM Z® Personal Development Tool (zPDT), ensure that the server has a minimum of 2 GB of real memory.
- Otherwise, ensure that the LPAR has a minimum of 8 GB of real memory.
Reference information
For more information about the minimum real memory requirement, see z/OS Planning for Installation.