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Function To perform the following functions: - Modify the checkpoint definition.
- Initiate a checkpoint reconfiguration dialog with JES2 .
Syntax
>>-$T--CKPTDEF -+-----------------------+----------------------->
'-,--DUPLEX--=--+-OFF-+-'
'-ON--'
>--+------------------------+----------------------------------->
'-,--MODE--=--+-DUAL---+-'
'-DUPLEX-'
>--+---------------------------------------------------+-------->
| .-,-----------------------. |
| V | |
'-,--NEWCKPT1--=--( ---+-DSName--=--dsname---+-+--)-'
+-STRname--=--strname-+
'-VOLser--=--volser---'
>--+---------------------------------------------------+-------->
| .-,-----------------------. |
| V | |
'-,--NEWCKPT2--=--( ---+-DSName--=--dsname---+-+--)-'
+-STRname--=--strname-+
'-VOLser--=--volser---'
>--+-------------------------+--+-------------------------+----->
'-,--OPVERIFY--=--+-----+-' '-,--RECONFIG--=--+-No--+-'
+-No--+ '-Yes-'
'-Yes-'
>--+-------------------------------------------------+---------->
| .-,---------------------. |
| V | |
'-,--VERSIONS--=--( ---+-NUMBER--=--number-+-+--)-'
'-WARN--=--warn-----'
>--+------------------------------------------------------+----><
| .-,--------------------------. |
| V | |
'-,--VOLATILE--=--( ---+-ALLCKPT--=--+-DIALOG-+-+-+--)-'
| +-IGNORE-+ |
| '-WTOR---' |
'-ONECKPT--=--+-DIALOG-+-'
+-IGNORE-+
'-WTOR---'
Parameters - DUPLEX={OFF|ON}
- Specifies whether this member of the multi-access spool configuration
uses the duplexing function.
- OFF
- No writes are made to the CKPT2 duplex data set from this member
of the multi-access spool configuration.
- ON
- CKPT2 is used as a backup of the CKPT1 data set, if MODE=DUPLEX
has been specified on the CKPTDEF initialization statement.
Note: - If MODE=DUPLEX has been specified on the CKPTDEF initialization
statement, at least one member of the MAS should specify DUPLEX=ON.
If no member specifies DUPLEX=ON, an I/O error on the CKPT1 data set
is disastrous to your single member or multi-access spool complex
if JES2 also fails.
It is recommended that all members specify
DUPLEX=ON unless CKPT2 must be placed on a volume that may be reserved
for other uses. In this case you should limit the number of members
specifying DUPLEX=ON to avoid availability problems.
- If MODE=DUPLEX and only one of the CKPTn data sets is marked INUSE=YES,
DUPLEX=ON is not allowed. If you try to set DUPLEX=ON, JES2 issues
the $HASP288 message and forces DUPLEX to OFF.
- If MODE=DUAL, JES2 does not use the value assigned to the DUPLEX=
parameter.
If any CKPT data sets are defined as being
on CF (CKPT1, CKPT2, NEWCKPT1, NEWCKPT2) then the mode must be DUPLEX
and it cannot be altered.
If both checkpoint data
sets are in use, to change to DUAL mode, all active members must have
DUPLEX=ON. If any member is DUPLEX=OFF, the command will fail with
a $HASP003 message.
Scope: Single Member.
- MODE=DUAL|DUPLEX
- Specifies whether the multi-access spool configuration will use
the data set defined by CKPT2= as the alternate primary checkpoint
data set (DUAL) or as the backup to the CKPT1 data set (DUPLEX).
- DUAL
- Specifies that the data set specified by CKPT2 be used as the
alternate primary checkpoint data set. The two data sets, specified
by CKPT1= and CKPT2= are used in a “flip-flop” alternating scheme.
(Refer to z/OS JES2 Initialization and Tuning Guide, SA32-0991 for a further
discussion of DUAL mode processing.)
If any checkpoint data set
resides on a coupling facility (STRname= is coded for CKPT1, CKPT2,
NEWCKPT1, or NEWCKPT2), JES2 forces the MODE= parameter to DUPLEX.
- DUPLEX
- Specifies that the data set specified by CKPT2 be used as the
backup to the primary checkpoint data set. The data set specified
by CKPT1= is the primary checkpoint data set and the data set specified
by CKPT2= is the backup (duplex) checkpoint data set. (Refer to z/OS JES2 Initialization and Tuning Guide, SA32-0991 for a further
discussion of DUPLEX mode processing.)
Note: - If you specify MODE=DUAL, the DUPLEX= specification is ignored.
- If you specify MODE=DUPLEX and DUPLEX=OFF for a specific member
of the multi-access spool configuration, that member will neither
use nor allocate a backup (CKPT2=) checkpoint data set.
- If you specify MODE=DUPLEX and DUPLEX=ON for a specific member
of the multi-access spool configuration, that member will use
the data set defined by CKPT2= as the backup checkpoint data set.
- The MODE= parameter must be specified the same for all members
of the multi-access spool configuration.
- The MODE= parameter can be changed through Operator
Command.
- The DUPLEX value does not affect the CKPTn INUSE setting
of the multi-access spool configuration.
Performance Considerations: If you specify
MODE=DUAL on CKPTDEF, also specifying HOLD=99999999 on the MASDEF
statement causes performance degradation. If you must use HOLD=99999999
on MASDEF, be certain to also specify MODE=DUPLEX on CKPTDEF.
- NEWCKPTn=(DSName=dsname)|(STRname=strname)|VOLser=volser)
- Specifies the alternate checkpoint data sets that can be used to
replace the CKPTn data sets. Should either CKPTn data set experience
a failure or otherwise become unavailable, NEWCKPT1 could replace
CKPT1 and NEWCKPT2 could replace CKPT2.
The DSNAME= parameter
and the VOLSER= parameter are mutually exclusive with the STRNAME=
parameter. To remove the value for this parameter without specifying
a replacement, specify null values: $T CKPTDEF,NEWCKPT1=(DSN=,VOL=)
-or- $T CKPTDEF,NEWCKPT1=(STR=)
- DSName=dsname
- The (1 to 44 character) name of the NEWCKPTn data set.
- STRname=strname
- Specifies the 1 to 16 character name of the coupling facility structure
to be used as a checkpoint data set. This structure must have been
defined in the coupling facility policy. The name can contain numeric,
uppercase alphabetic, dollar sign ($), at sign (@), pound sign (#),
or underscore (_) characters.
You cannot specify the same STRNAME=
subparameter for the NEWCKPTn= parameter as that on the CKPTn parameter;
the coupling facility does not allow the CKPTn structure name to be
forwarded to the NEWCKPTn structure name.
- VOLser=volser
- The volume serial number on which the data set specified by DSName
resides. Although it is not a system requirement that all four checkpoint
data sets (CKPT1, CKPT2, NEWCKPT1, NEWCKPT2) reside on separate volumes,
it is strongly recommended that at least CKPT1 and CKPT2 reside
on their own volumes.
Note: - Although it is not a system requirement that you predefine the
NEWCKPTn data sets (either on the CKPTDEF initialization statement
or using the $T CKPTDEF command), it is recommended that you do so
for ease of use. If you issue the $T CKPTDEF,NEWCKPTn=... command
on any one member in the multi-access spool configuration and wait
a sufficient length of time (based on the individual systems' HOLD=
specifications), that change is reflected across all active members
through the CKPTn data set(s).
- If you do not predefine the NEWCKPTn data sets, you may dynamically
define them when and if needed during the reconfiguration dialog.
- If you change the NEWCKPTn values (either using the $T CKPTDEF
command or during the dialog) and then warm start JES2, the values
of NEWCKPTn in the CKPTn data set(s) are used instead of those specified
on the CKPTDEF initialization statement (unless PARM=RECONFIG was
specified, in which case the values from the CKPTDEF statement are
used).
Scope: MAS-Wide.
- OPVERIFY=[No|Yes]
- Displays whether (Yes) or not (No) JES2 prompts the operator during
a JES2-initiated I/O error checkpoint reconfiguration to verify or
alter the default reconfiguration action. JES2 propagates this parameter
specification to all members in the MAS. OPVERIFY has no meaning for
a checkpoint reconfiguration entered for any other reasons.
- No
- Suppresses operator verification during the checkpoint reconfiguration
dialog. JES2 takes the following default reconfiguration actions:
- For message $HASP273, JES2 replaces the checkpoint data set with
its replacement data set defined on the NEWCKPTn parameter of the
CKPTDEF statement.
- For message $HASP278, when JES2 cannot locate the specified replacement
checkpoint data set, JES2 automatically creates one. This new checkpoint
data set can always be defined on DASD, but if you require that it
be a new coupling facility structure, JES2 can only create it if you
previously defined the coupling facility resource management (CFRM)
policy. JES2 cannot dynamically create a CFRM policy even if the original
checkpoint was defined as a coupling facility structure. Refer to z/OS MVS Setting Up a Sysplex, SA23-1399 for
information on how to define a CFRM policy.
- Yes
- JES2 prompts the operator during the checkpoint reconfiguration
when entered by JES2 for I/O errors only to respond to message
pairs $HASP273 and $HASP272 or $HASP278 and $HASP272.
Scope: MAS-Wide.
- RECONFIG={No|Yes}
- Specifies whether JES2 should enter the checkpoint reconfiguration
dialog.
- No
- JES2 does not enter the checkpoint reconfiguration dialog.
- Yes
- JES2 enters the checkpoint reconfiguration dialog so that you
can supply the information needed for the checkpoint data set specifications.
The dialog allows you to allocate an existing backup data set, create
a new data set to replace the checkpoint data set currently in use,
or suspend the use of a data set. No other JES2 processing is done
during a checkpoint reconfiguration dialog.
If you specify RECONFIG=Y,
you must not specify any other operands on the $T CKPTDEF command
because:
Scope: MAS-Wide.
- VERSIONS=(NUMBER=nn|WARN=mmm)
- Indicates modification to the checkpoint versioning parameter.
- NUMBER=nn
- Changes the maximum number (2-50) of versions of the checkpoint data set that JES2 maintains.
Too low a number could result in an application program having to
use a copy that does not contain the most recent checkpoint data.
Default: Set by JES2
- WARN=mmm
- Changes a percent (0-100) usage threshold of versions of the checkpoint
data set. When the percentage of checkpoint data versions reaches
this threshold, the operator is alerted with the message $HASP050
JES2 RESOURCE SHORTAGE. If you specify 0, no alert is given.
Default: Set by JES2
Scope: Single Member.
- VOLATILE=
- Specifies how JES2 should respond when a checkpoint data set that
resides on a coupling facility enters the state where, if power to
the coupling facility is lost, all data on the coupling facility is
lost.
This parameter does not apply when a coupling facility structure
becomes volatile during the checkpoint reconfiguration dialog.
Before modifying this parameter, consult with your systems programmer
and refer to z/OS JES2 Initialization and Tuning Guide, SA32-0991. - ALLCKPT=
- Specifies the action that should be taken if all available checkpoint
data sets (INUSE=YES) reside on coupling facilities that become volatile
(unstable).
If only one checkpoint resides on a coupling facility,
JES2 uses the ALLCKPT subparameter setting. - DIALOG
- Specifies that JES2 enters the checkpoint reconfiguration dialog.
- IGNORE
- Specifies that JES2 ignores when a coupling facility becomes volatile
(unstable).
- WTOR
- Specifies that JES2 issues a WTOR so the operator can determine
whether to suspend or continue use of the checkpoint(s) that reside
on coupling facility structure(s).
- ONECKPT=
- Specifies the action taken if the coupling facility on which a
checkpoint data set resides becomes volatile (unstable).
JES2
uses the ONECKPT= subparameter settings if: - Only one of the two checkpoint data sets resides on a coupling
facility structure and that coupling facility becomes volatile.
- Both checkpoint data sets reside on a coupling facility, but only
one becomes volatile.
- DIALOG
- Specifies that JES2 enters the checkpoint reconfiguration dialog.
- IGNORE
- Specifies that JES2 ignores when the coupling facility becomes
volatile (unstable).
- WTOR
- Specifies that JES2 issues a WTOR so the operator can determine
whether to suspend or continue use of the checkpoint that resides
on a coupling facility structure.
Scope: Single member.
Authority Required This command requires system authority. The description of the $T RDRnn command explains
how to ensure that the authority of the appropriate MVS™ system
command group is assigned.
This command requires control security access authority. For a description of assigning command
input authority, see z/OS JES2 Initialization and Tuning Guide, SA32-0991.
Processing Considerations If JES2 is currently
in the checkpoint reconfiguration dialog, the $T CKPTDEF command is
not accepted. JES2 issues the $HASP003 message with RC=30, which indicates
the device change request is prohibited.
Scope The scope of this command
varies by parameter. See the description of each parameter for its
scope.
The values supplied for some parameters on this command
will be in effect across the entire MAS, while the values supplied
for other parameters will be in effect for this member only.
Depending on your installation's setup, you might want the parameters
for this command to be applied to all members of the MAS (to ensure
a consistent environment across the MAS). If so, you can use the MVS ROUTE *ALL command to issue this command to all active members
(if the JES2 command character is the same on all members). See z/OS MVS System Commands, SA38-0666 for more
information on using the ROUTE *ALL command.
Messages The $HASP829 message displays
the current values of all the parameters on the CKPTDEF initialization
statement.
Example 1 $t ckptdef,newckpt1=(dsn=sys1.replace1,vol=j2com1),
newckpt2=(dsn=sys1.replace2,vol=j2com1)
$HASP829 CKPTDEF CKPT1=(DSNAME=SYS1.JESCKPT1,VOLSER=DATA1,
$HASP829 INUSE=YES,VOLATILE=NO),
$HASP829 CKPT2=(DSNAME=SYS1.JESCKPT2,VOLSER=DATA1,
$HASP829 INUSE=YES,VOLATILE=NO),
$HASP829 NEWCKPT1=(DSNAME=SYS1.REPLACE1,VOLSER=J2COM1),
$HASP829 NEWCKPT2=(DSNAME=SYS1.REPLACE2,VOLSER=J2COM1),
$HASP829 MODE=DUAL,DUPLEX=ON,LOGSIZE=4,APPLCOPY=NONE,
$HASP829 VERSIONS=(STATUS=INACTIVE,NUMBER=2,WARN=80,
$HASP829 MAXFAIL=0,NUMFAIL=0,VERSFREE=2,MAXUSED=0),
$HASP829 RECONFIG=NO,VOLATILE=(ONECKPT=WTOR,
$HASP829 ALLCKPT=WTOR),OPVERIFY=YES
If the data set and/or volume, on which CKPT1 resides,
has a failure, JES2 assigns CKPT1 to the SYS1.REPLACE1 data set on
volume J2COM1. If the data set and/or volume on which CKPT2 resides
has a failure, JES2 assigns CKPT2 to the SYS1.REPLACE2 data set on
volume J2COM1.
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