Specifying each CMAS correctly in IEASYSxx
In every z/OS® image that contains a CMAS, verify that the IEASYSxx member of the SYS1.PARMLIB library that you use for z/OS initialization includes the MAXCAD and NSYSLX parameters.
MAXCAD=nnn-
Set the value to include the number of SCOPE=COMMON MVS™ data spaces that are required for each LPAR. This value will impact the number of concurrent CMASes that can run on each LPAR.
Each CMAS requires a number of SCOPE=ALL data spaces. This number depends on the
CACHEDSNUM value for the CMAS. This setting controls the number of data spaces
allocated for each component, except the data cache manager, which has only one data space.
Therefore, the number of SCOPE=ALL data spaces required for a CMAS can be calculated as follows:
number of SCOPE=ALL data spaces = ( 9 * CACHEDSNUM ) + 1The default value of the CACHEDSNUM parameter is 2, and
normally you do not change it unless advised to do so by IBM®
Support. Therefore, each CMAS typically requires 19 SCOPE=ALL data spaces.Include any SCOPE=COMMON data spaces that might be in use by other products in the MAXCAD value.
The lower the MAXCAD value, the more CMASs can be run at the same time on the LPAR.
At CMAS start-up, if MVS™ cannot allocate the required number of SCOPE=ALL data spaces, CICSPlex® SM produces message EYUXC0011E with a return code of '0000000C' and the CMAS shuts down. To reduce the chance of this happening, either lower theMAXCAD value if possible, or plan to reduce the number of CMASes on the LPAR.
Calculate the maximum number of CMASes that you can have on the LPAR at this CICS® release as follows. Be aware that other releases of CICS TS might have different requirements:- Subtract the maximum number of entries in the PASN-AL (510) from the current
MAXCAD value. This provides the number of PASN-AL entries that remain available
for use by the Environment Services System Services (ESSS) address space to access the required data
spaces. For example:
- If MAXCAD is set to the maximum possible value of 250, and the PASN-AL limit is 510, the calculation is: 510 (PASN-AL limit) - 250 (MAXCAD value) = 260 available entries left on the PASN-AL.
- Divide the remaining PASN-AL entries by the number of SCOPE=ALL data spaces that each CMAS
requires. This is the number of CMASes per release that can be started at the same time on the LPAR.
For example, taking the number of PASN-AL entries from the previous step:
- Each CMAS typically uses 19 SCOPE=ALL data spaces, so the calculation is: 260/19
= 13.68. The maximum number of CMASs on the LPAR is 13.
To establish the count of SCOPE=ALL data spaces that are allocated to the ESSS, issue this command from z/OS:
The last 4 bytes of the DSPNAME contain the SYSID of each CMAS./D A,EYUX540 - Subtract the maximum number of entries in the PASN-AL (510) from the current
MAXCAD value. This provides the number of PASN-AL entries that remain available
for use by the Environment Services System Services (ESSS) address space to access the required data
spaces. For example:
NSYSLX=nnn- Set or increase the value to include the minimum number of linkage indexes (LXs) that are required by CICSPlex SM. One LX is required for the Environment Services System Services (ESSS), so the minimum number of LXs required for use by CICSPlex SM is one.
For more information about this parameter, see the z/OS Initialization and Tuning Reference manual.