Understanding how to modify PFA checks

PFA checks work differently than traditional checks. Although you can modify PFA checks using the IBM® Health Checker for z/OS® commands and policies (as described in IBM Health Checker for z/OS User's Guide), modifications to the PFA checks are unique in the following ways:

How to quiesce a PFA check:
Use the MODIFY command to quiesce a PFA check. If the check is to permanently quiesce until PFA restarts, use the MODIFY command to delete the check. Because PFA checks are remote health checks, you must restart PFA to add a previously deleted check. If the check is to be quiesced now, but restarted later while PFA is still running, use the MODIFY command to deactivate the check. Deactivating a check stops the comparisons from occurring, but to stop collection and modeling you must set the COLLECTINACTIVE parameter to 0. To stop collections, modeling, and comparisons for an individual check so that the check can be reactivated without restarting PFA, do the following:
1. First , stop PFA from collecting and modeling data by setting the COLLECTINACTIVE parameter to zero. For example:
```
f hzsproc,update,check(ibmpfa,pfa_logrec_arrival_rate),
parm('collectinactive(0)')
```
2. Next, deactivate the check in IBM Health Checker for z/OS. For example:
```
f hzsproc,deactivate,check(ibmpfa,pfa_logrec_arrival_rate)	
```
Use the MODIFY pfa DISPLAY command to display the check-specific parameters:
You can use the MODIFY pfa,DISPLAY command to display the cumulative set of modified, check-specific parameters that are currently in use by a PFA check. See MODIFY PFA, DISPLAY for more information.
Use the MODIFY pfa UPDATE command to read specific PFA configuration files:
You can use the MODIFY pfa,UPDATE command to read certain configuration files that a check supports. See MODIFY PFA, UPDATE.
Using the MODIFY hzsproc command to modify individual PFA check parameters:
You can use the MODIFY hzsproc command to modify individual parameters of PFA checks. When specifying the PARM parameter on f hzsproc,update for PFA checks, you do not have to specify all check-specific parameters. The parameters that are not specified are not changed. If the parameters were not previously modified, the values remain the default values. If the parameters were previously modified, the previously specified values remain.
The following example of the MODIFY hzsproc command sets the debug parameter for PFA to ON.
```
f hzsproc,update,check(IBMPFA,PFA_COMMON_STORAGE_USAGE),parm('debug(1)')
```
The rest of the check-specific parameters retain their default values as follows:
```
CHECK SPECIFIC PARAMETERS:
       COLLECTINT                  : 15
       MODELINT                    : 360
       COLLECTINACTIVE             : 1=ON
       DEBUG                       : 1=ON
       THRESHOLD                   : 2
```
If the check is displayed using IBM Health Checker for z/OS interfaces, the user supplied parameters are displayed as either:
```
USER SUPPLIED PARAMETERS:  debug(1)
```
or
```
CHECK PARM: debug(1)
```
Then, when the following command is entered:
```
f hzsproc,update,check(IBMPFA,PFA_COMMON_STORAGE_USAGE),parm('collectint(10) modelint(60)') 
```
the values for the check change to:
```
CHECK SPECIFIC PARAMETERS:
       COLLECTINT                  : 10
       MODELINT                    : 60
       COLLECTINACTIVE             : 1=ON
       DEBUG                       : 1=ON
       THRESHOLD                   : 5
```
If the check is displayed again using IBM Health Checker for z/OS interfaces, the user-supplied parameters that are displayed are the last ones specified on the MODIFY command as follows:
```
USER SUPPLIED PARAMETERS:  collectint(10) modelint(60)
```
or
```
CHECK PARM: collectint(10) modelint(60)
```
This is not the cumulative list of parameters currently in use by the check. Therefore, to display the current parameter values being used by the check, use the f pfa,display,checks,detail command as listed in MODIFY PFA, DISPLAY.
The debug parameter is a PFA check-specific parameter.
The debug parameter is a check-specific parameter and not the same debug parameter as the one in IBM Health Checker for z/OS. The debug parameter within IBM Health Checker for z/OS applies only to the phase of performing the check when the interval is reached and not to all other phases, such as data collection and modeling that are done internally within the PFA checks. Therefore, the debug parameter within IBM Health Checker for z/OS has no meaning to PFA and is ignored.
To set the debug parameter for PFA checks, specify it as a parm as in the following example:
```
f hzsproc,update,check(IBMPFA,PFA_CHECK_NAME),parm('debug(1)')
```
Each PFA check contains more information about its check-specific parameter.