DEFINE LOGSTREAM keywords and parameters

The DEFINE LOGSTREAM specification requests that an entry for a log stream is to be defined in the LOGR policy. The keywords are explained as follows:

[GROUP=(PRODUCTION|TEST)]

An optional keyword input that specifies whether the log stream is in the test group or the production group. This keyword allows you to keep processing and resources for log streams in the two groups separate on a single system, including requests such as data set allocation and data set recalls. If the TEST group fails, the failure does not normally affect the PRODUCTION group. The active primary TYPE=LOGR couple data set in the sysplex must be formatted at a z/OS Version 1 Release 2 (HBB7705) or higher format level in order to specify the GROUP keyword. Otherwise, the request will fail with a return code 8, reason code 0839.

If you specify GROUP(PRODUCTION), which is the default, system logger places this log stream in the PRODUCTION group. A PRODUCTION log stream can use at least 75% of the system logger couple data set DSEXTENT records and connection slots.

If you specify GROUP(TEST), system logger places this log stream in the TEST group. TEST log streams are limited to at most 25% of the system logger couple data set DSEXTENT records and connection slots.

The GROUP value you specify must match the group setting for the structure that the log stream is being defined for, because system logger does not allow you to define a mixture of TEST and PRODUCTION log streams to a single structure. When you define the first log stream to a structure, the structure becomes either a TEST or PRODUCTION structure. After that, the GROUP value for subsequent log streams defined to a structure must match the GROUP value of the initial log stream. For example, if you specify or default to GROUP(PRODUCTION) for the first log stream defined to a structure, you will only be able to define PRODUCTION log streams to that structure subsequently.

NAME(streamname)

Specifies the name of the log stream that you want to define in the LOGR policy. The name can be made up of one or more segments separated by periods, up to the maximum length of 26 characters. The following rules apply:

Each segment can contain up to eight numeric, alphabetic, or national ($, #, or @) characters.
The first character of each segment must be an alphabetic or national character.
Each segment must be separated by periods, which you must count as characters.

RMNAME(NO_RMNAME

RMNAME(rmname)

Specifies the name of the resource manager program associated with the log stream. If you specify RMNAME(NO_RNAME), which is the default, the macro will be invoked as if RMNAME was not specified. RNAME must be 8 alphanumeric or national ($,#,or @) characters, padded on the right with blanks if necessary.

You must define RMNAME in the LOGR policy before the resource manager can connect to the log stream.

See the system logger chapter in z/OS MVS Programming: Assembler Services Guide for information about writing a resource manager program to back up a log stream.

DESCRIPTION(description)

Specifies the user defined data describing the log stream. DESCRIPTION must be 16 alphanumeric or national ($,#,@) characters, underscore (_) or period (.), padded on the right with blanks if necessary.

DASDONLY(NO)

DASDONLY(YES)

Specifies whether the log stream being defined is a coupling facility or a DASD-only log stream.

If you specify DASDONLY(NO), which is the default, the log stream is defined as a coupling facility log stream. With DASDONLY(NO), you can also specify STG_DUPLEX, DUPLEXMODE, and LOGGERDUPLEX keyword to select a method of duplexing for a coupling facily log stream.

If you specify DASDONLY(YES) the log stream is defined as a DASD-only log stream and does not use the coupling facility for log data.

Because a staging data set is required when using a DASD-only log stream, check the usage of the STG_SIZE parameter, the STG_DATACLAS parameter, or the defaults used for sizing the staging data set.

DASD-only log streams are unconditionally duplexed to staging data sets. This means that DASD-only log streams are created as if STG_DUPLEX(YES), DUPLEXMODE(UNCOND), and LOGGERDUPLEX(UNCOND) were specified when the log stream was defined. You cannot change these duplexing parameters. However, you can specify STG_DUPLEX(YES), DUPLEXMODE(UNCOND), and LOGGERDUPLEX(UNCOND). If you specify any other parameters for these keywords when you define a DASD-only log stream, the define request will fail. These keywords are optional.

With DASDONLY(NO), you can specify STG_DUPLEX,DUPLEXMODE, and LOGGERDUPLEX keywords to select a method of duplexing for a coupling facility log stream.

STRUCTNAME(structname)

Specifies the up to 16 character name of the coupling facility structure associated with the coupling facility log stream being defined. The structure specified is a list structure defined in the CFRM policy where all of this log stream's log blocks will be written before being written to DASD.

For a coupling facility log stream, you must define STRUCTNAME in the log stream definition in the LOGR policy via this parameter or the STRUCTNAME defined for the log stream referenced by the LIKE parameter before you can connect to the log stream.

For a DASD-only log stream, omit the STRUCTNAME parameter, since there is no coupling facility associated with the log stream.

STRUCTNAME must be 16 alphanumeric or national ($,#,@) characters, or underscore (_), padded on the right with blanks if necessary. The first character must be alphabetic.

MAXBUFSIZE(maxbufsize)

MAXBUFSIZE(65532)

Specifies the size, in bytes, of the largest log block that can be written to the DASD-only log stream being defined in this request.

The value for MAXBUFSIZE must be between 1 and 65,532 bytes. The default is 65,532 bytes.

You can only specify the MAXBUFSIZE on a structure definition for a DASD-only log stream. For a coupling facility structure, specify MAXBUFSIZE in the structure definition.

STG_DUPLEX(NO)

STG_DUPLEX(YES)

Specifies whether the log stream data for a coupling facility log stream should be duplexed in DASD staging data sets.

For coupling facility log streams:

The default is STG_DUPLEX(NO). If you specify or default to STG_DUPLEX(NO), log data for a coupling facility log stream will be duplexed in local buffers, which might be vulnerable to system failure if your configuration contains a single point of failure.

If you specify STG_DUPLEX(YES), log data for a coupling facility log stream will be duplexed in staging data sets when the conditions defined by the DUPLEXMODE keyword are met. This method safeguards data on DASD staging data sets.

You can use the DUPLEXMODE keyword with STG_DUPLEX and with LOGGERDUPLEX to specify the type of duplexing desired and whether you want conditional or unconditional duplexing by System Logger.

For DASD-only log streams:

You can either omit this keyword or specify STG_DUPLEX(YES). In either case, log data will be unconditionally duplexed to staging data sets. Specifying any other parameter for the STG_DUPLEX keyword will result in an error for DASD-only log streams. See the LOGGERDUPLEX keyword for additional duplexing options.

DUPLEXMODE(COND)

DUPLEXMODE(UNCOND)

DUPLEXMODE(DRXRC)

Specifies the conditions under which the log data for a log stream should be duplexed in DASD staging data sets.

For coupling facility log streams:

The default is DUPLEXMODE(COND). If you specify or default to DUPLEXMODE(COND), the coupling facility log data will be duplexed in staging data sets only if a system's connection to the coupling facility log stream contains a single point of failure and is therefore vulnerable to permanent log data loss:

A connection to a log stream contains a single point of failure if the coupling facility is volatile or resides on the same CPC as the MVS™ system connecting to it. The coupling facility log data for the system connection containing the single point of failure will be duplexed to staging data sets.
A connection to a log stream is failure-independent when the coupling facility for the log stream is non-volatile and resides on a different central processor complex (CPC) than the MVS system connecting to it. The coupling facility log data for that system connection will not be duplexed to staging data sets.

If you specify DUPLEXMODE(UNCOND), the log data for the coupling facility log stream will be duplexed in staging data sets, unconditionally, even if the connection is failure independent.

If you specify DUPLEXMODE(DRXRC), the log data for the coupling facility log stream will be duplexed in staging data sets, unconditionally, but only for specific disaster recovery purposes. Use this option when you always want to use staging data sets for specific disaster recovery situations and not use them for any local system log data recovery.

The DRXRC option is supported on z/OS® HBB7720 and higher release levels. The active primary TYPE=LOGR couple data set in the sysplex must be formatted at a z/OS Version 1 Release 2 (HBB7705) or higher format level in order to specify the DRXRC option for the DUPLEXMODE keyword. Otherwise, the request will fail with a return code 8, reason code 0839.

The type of log data duplexing that occurs for any data written to the coupling facility structure will be as follows:

If the structure is in simplex-mode:
1. duplexing to local buffers for any local sysplex system log data rebuild/recovery use,
2. plus, duplexing to DRXRC-type staging data sets for any secondary/recovery site system disaster recovery use.
If the structure is in duplex-mode:
1. duplexing to the 2nd structure instance (provided by XES), and
2. duplexing to local buffers for any local sysplex system log data rebuild/recovery use, when LOGGERDUPLEX=UNCOND is also specified or there is a failure-dependence configuration,
3. plus, duplexing to DRXRC-type staging data sets for any secondary/recovery site system disaster recovery use.
With the DUPLEXMODE=DRXRC specification, System Logger will duplex the log stream data written to a Coupling Facility structure in a staging data set in an asynchronous manner. The DASD mirroring protocol of the staging data set is done using eXtended Remote Copy (XRC) and the staging data set is part of an XRC DASD consistency group.

Any log stream staging data set defined for this use will only be usable for recovery purposes when a system is IPL'd with the DRMODE=YES specification along with a Y response to System Logger message IXG068D. This type of IPL would normally be done when a secondary/recovery site system is IPL'd to handle the start up following a disaster situation for the primary (main) sysplex systems. Once these log streams are recovered in this situation, the log stream attributes are also updated to indicate STG_DUPLEX=NO so no staging data set duplexing will be in effect for these log streams.

See Plan DRXRC-type staging data sets for coupling facility log streams for more details on establishing the appropriate environment for this duplexing approach.

You can use the DUPLEXMODE keyword with STG_DUPLEX and with LOGGERDUPLEX to specify the type of duplexing desired and whether you want conditional or unconditional duplexing by System Logger. See Selecting a method of duplexing coupling facility log data for complete information about using staging data sets to duplex coupling facility log data.

DUPLEXMODE is valid only when STG_DUPLEX(YES) is also specified.

Note: The staging data set related keywords, STG_SIZE, STG_DATACLAS, STG_MGMTCLAS, and STG_STORCLAS will remain set for the log stream and be used for any dynamic staging data set allocation during local recovery even after the conversion to STG_DUPLEX=NO.

For DASD-only log streams:

You can either omit this keyword or specify DUPLEXMODE(UNCOND). In either case, log data will be unconditionally duplexed to staging data sets. Specifying any parameter other than UNCOND for the DUPLEXMODE keyword will result in error for DASD-only log streams.

LOGGERDUPLEX(UNCOND)

LOGGERDUPLEX(COND)

Specifies whether System Logger will continue to provide its own log data duplexing, or conditionally not provide its own duplexing based on an alternative duplexing configuration that provides an equivalent or better recoverability of the log data.

For coupling facility log streams, the default parameter is LOGGERDUPLEX(UNCOND).

The active primary TYPE=LOGR couple data set in the sysplex must be formatted at a z/OS Release 2 or higher level in order to specify this keyword. Otherwise, the request will fail with a return code 8, reason code 0839.

For coupling facility log streams:

LOGGERDUPLEX(UNCOND) indicates that System Logger will provide its own specific duplexing of the log data regardless of any other duplexing (such as system-managed duplexing rebuild) that may be occurring.

LOGGERDUPLEX(COND) indicates that logger will provide its own specific duplexing of the log data unless the log stream is in an alternative duplexing configuration that provides an equivalent or better recoverability of the log data. For example, System Logger will not provide its own duplexing of the log data in the following configuration:

When the log stream is in a non-volatile coupling facility list structure that is in a system-managed duplexing rebuild process (duplex mode)
There is a failure independent relationship between the two structure instances, and
There is a failure independent connection between connecting system and composite structure view.

See Logger and coupling facility duplexing combinations and System logger recovery for additional considerations on using the LOGGERDUPLEX keyword.

See Case 5 in Table 1 for additional details about the above configuration.

Note: When DUPLEXMODE=DRXRC is specified for the log stream, system logger will unconditionally duplex log data to a DRXRC-type staging data set in addition to the logger duplexing or system-managed duplexing used for the systems log data rebuild/recovery activity at primary site.

For DASD-only log streams:

You can either omit this keyword or specify the default of LOGGERDUPLEX(UNCOND). In either case, log data will be unconditionally duplexed to staging data sets. Specifying any other parameter for the LOGGERDUPLEX keyword will result in an error for DASD-only log streams.

STG_DATACLAS(NO_STG_DATACLAS)

STG_DATACLAS(stg_dataclas)

Specifies the up to 8-byte name of the SMS data class that will be used for allocation of the DASD staging data set for this log stream. The first character must be an alphabetic or national character.

If you specify STG_DATACLAS(NO_STG_DATACLAS), which is the default, the data class is defined by standard SMS processing. See z/OS DFSMS Using Data Sets for more information about SMS. An SMS value specified on the STG_DATACLAS parameter, including NO_STG_DATACLAS, always overrides one specified on a model log stream used on the LIKE parameter.

STG_MGMTCLAS(NO_STG_MGMTCLAS)

STG_MGMTCLAS(stg_mgmtclas)

Specifies the up to 8-byte name of the SMS management class for the allocation of the DASD staging data set for this log stream. The first character must be an alphabetic or national character.

If you specify STG_MGMTCLAS(NO_STG_MGMTCLAS), which is the default, the management class is defined by standard SMS processing. See z/OS DFSMS Using Data Sets for more information about SMS. An SMS value specified on the STG_MGMTCLAS parameter, including NO_STG_MGMTCLAS, always overrides one specified on a model log stream used on the LIKE parameter.

STG_STORCLAS(NO_STG_STORCLAS)

STG_STORCLAS(stg_storclas)

Specifies the up to 8-byte name of the SMS storage class for allocation of the DASD staging data set for this log stream. The first character must be an alphabetic or national character.

If you specify STG_STORCLAS(NO_STG_STORCLAS), which is the default, the storage class is defined by standard SMS processing. See z/OS DFSMS Using Data Sets for more information about SMS. An SMS value specified on the STG_STORCLAS parameter, including NO_STG_STORCLAS, always overrides one specified on a model log stream used on the LIKE parameter.

STG_SIZE(stg_size)

Specifies the size, in 4K blocks, of the DASD staging data set for the log stream being defined. The actual data set size of your data set depends on many factors including track size, CI SIZE, and volume type, and may be smaller or larger than your parameter inputs expect. See Testing log data set parameter modifications for important notes on choosing a data set size.

Specifying STG_SIZE overrides the space allocation attribute on the STG_DATACLAS parameter, if specified.

If you omit STG_SIZE for a coupling facility log stream, system logger does one of the following, in the order listed, to allocate space for staging data sets:

Uses the STG_SIZE of the log stream specified on the LIKE parameter, if specified.
Uses the maximum coupling facility structure size for the structure to which the log stream is defined. This value is obtained from the value defined on the SIZE parameter for the structure in the CFRM policy.

If you omit STG_SIZE for a DASD-only log stream, system logger does one of the following, in the order listed, to allocate space for staging data sets:

Uses the STG_SIZE of the log stream specified on the LIKE parameter, if specified.
Uses the size defined in the SMS data class for the staging data sets.
Uses dynamic allocation rules for allocating data sets, if SMS is not available.

LS_DATACLAS(NO_LS_DATACLAS)

LS_DATACLAS(ls_dataclas)

Specifies the up to 8-byte name of the SMS data class that will be used for log stream offload data set allocation. The first character must be an alphabetic or national character.

If you specify LS_DATACLAS(NO_LS_DATACLAS), which is the default, the data class is defined by standard SMS processing. See z/OS DFSMS Using Data Sets for more information about SMS. An SMS value specified on the LS_DATACLAS parameter, including NO_LS_DATACLAS, always overrides one specified on a model log stream used on the LIKE parameter.

LS_MGMTCLAS(NO_LS_MGMTCLAS)

LS_MGMTCLAS(ls_mgmtclas)

Specifies the up to 8-byte name of the SMS management class for the log stream offload data set allocation. The first character must be an alphabetic or national character.

If you specify LS_MGMTCLAS(NO_LS_MGMTCLAS), which is the default, the management class is defined by standard SMS processing. See z/OS DFSMS Using Data Sets for more information about SMS. An SMS value specified on the LS_MGMTCLAS parameter, including NO_LS_MGMTCLAS, always overrides one specified on a model log stream used on the LIKE parameter.

LS_STORCLAS(NO_LS_STORCLAS)

LS_STORCLAS(ls_storclas)

Specifies the up to 8-byte name of the SMS storage class for the log stream offload data set allocation. The first character must be an alphabetic or national character.

If you specify LS_STORCLAS(NO_LS_STORCLAS), which is the default, the storage class is defined by standard SMS processing. See z/OS DFSMS Using Data Sets for more information about SMS. An SMS value specified on the LS_STORCLAS parameter, including NO_LS_STORCLAS, always overrides one specified on a model log stream used on the LIKE parameter.

LS_SIZE(ls_size)

Specifies the size, in 4K blocks, of the log stream offload DASD data sets for the log stream being defined.

The actual data set size of your data set depends on many factors including track size, CI SIZE, and volume type, and may be smaller or larger than your parameter inputs expect. See Testing log data set parameter modifications for important notes on choosing a data set size.

Specifying LS_SIZE overrides the space allocation attribute on the LS_DATACLAS parameter, it was if specified.

If you omit LS_SIZE, system logger does one of the following to allocate offload data sets:

Uses the LS_SIZE of the log stream specified on the LIKE parameter, if specified.
Uses the size defined in the SMS data class for the offload data sets.
Uses dynamic allocation rules for allocating data sets, if SMS is not available.

AUTODELETE(NO)

AUTODELETE(YES)

Specifies when system logger can physically delete log data.

If you specify AUTODELETE(NO), which is the default, system logger physically deletes an entire log data set only when both of the following are true:

Data is marked for deletion by a system logger application using the IXGDELET service or an archiving procedure (like CICS/VR for CICS® log streams or IFBEREPS, which is shipped in SYS1.SAMPLIB, for logrec log streams).
The retention period for all the data in the log data set has expired.

If you specify AUTODELETE(YES), system logger automatically physically deletes log data whenever data is either marked for deletion (using the IXGDELET service or an archiving procedure) or the retention period for all the log data in a data set has expired.

Be careful when using AUTODELETE(YES) if the system logger application manages log data deletion using the IXGDELET service. With AUTODELETE(YES), system logger may delete data that the application expects to be accessible. If you specify AUTODELETE=YES with RETPD=0, data is eligible for deletion as soon as it is written to the log stream.

The LOGR couple data set must be formatted at the OS/390® Release 3 level or above to use this keyword.

RETPD(0)

RETPD(retpd)

Specifies the retention period, in days, for log data in the log stream. The retention period begins when data is written to the log stream. Once the retention period for an entire log data set has expired, the data set is eligible for physical deletion. The point at which system logger physically deletes the data depends on what you have specified on the AUTODELETE parameter.

System logger processes RETPD when a log data set fills and system logger switches to a new one for a log stream. System logger will not process a retention period or delete data on behalf of log streams that are not connected and being written to by an application.

The value specified for RETPD must be between 0 and 65,536.

HLQ(NO_HLQ)

HLQ(hlq)

Specifies the up to 8-byte high-level qualifier for both the log stream data set name and the staging data set name. HLQ must be 8 alphanumeric or national ($,#,or @) characters, padded on the right with blanks if necessary. The first character must be an alphabetic or national character.

If you do not specify a high-level qualifier, or if you specify HLQ(NO_HLQ), the log stream will have a high-level qualifier of IXGLOGR. If you specified the LIKE parameter, the log stream will have the high-level qualifier of the log stream specified on the LIKE parameter. The value specified for HLQ overrides the high-level qualifier for the log stream specified on the LIKE parameter.

HLQ and EHLQ are mutually exclusive and cannot be specified for the same log stream definition.

If the name specified for the HLQ parameter refers to a field that contains X'00', then the macro will be invoked as if NO_HLQ had been specified. However, specifying HLQ=NO_HLQ and EHLQ=ehlq on the same request results in an error. When HLQ=NO_HLQ is specified, then the resulting high-level qualifier will be determined by the EHLQ value from the LIKE log stream or using a default value.

EHLQ(NO_EHLQ)

EHLQ(ehlq)

Specifies the name (or address in a register) of a 33-byte input field containing the extended high-level qualifier for both the log stream data set name and the staging data set name.

Syntax requirements for the extended high-level qualifier are as follows:

The extended high-level qualifier must be 33 alphanumeric or national ($,#, or @) characters, padded on the right with blanks if necessary.
The value can be made up of one or more qualifiers (each 1 to 8 characters) separated by periods, up to the maximum length of 33 characters.
Each qualifier must contain up to eight alphabetic, national, or numeric characters. Lowercase alphabetic characters will be folded to uppercase.
The first character of each qualifier must be an alphabetic or national character.
Each qualifier must be separated by a period, which you must count as a character.
The resulting length of concatenating the significant characters from the EHLQ value with the STREAMNAME value (including the period delimiter) cannot exceed 35 characters.

EHLQ and HLQ are mutually exclusive and cannot be specified for the same log stream definition.

When the EHLQ parameter is not explicitly specified on the request, the resulting high-level qualifier to be used for the log stream data sets will be based on whether the HLQ or LIKE parameters are specified. If the HLQ parameter is specified, then that value will be used for the log stream data sets. When no high-level qualifier is explicitly specified on the DEFINE LOGSTREAM request, but the LIKE parameter is specified, then the high-level qualifier value being used in the referenced log stream will be used for the newly defined log stream. If the EHLQ, HLQ, and LIKE parameters are not specified, then the default value “IXGLOGR” will be used.

When EHLQ=NO_EHLQ is specified, then the resulting high-level qualifier will be determined by the HLQ value from the LIKE log stream or using a default value.

The active primary TYPE=LOGR couple data set must be formatted at a z/OS release 1.2 or higher level in order to specify the EHLQ keyword. Otherwise, the request will fail with return code 8, reason code X'0839'.

Examples:

Assume the OPERLOG log stream (NAME=SYSPLEX.OPERLOG) is defined with “EHLQ=MY.OWN.PREFIX” specified. The log stream data set would be allocated as follows, where the suffix is up to an eight-character field provided by System Logger.
```
MY.OWN.PREFIX.SYSPLEX.OPERLOG.suffix
```
Assume the OPERLOG log stream (NAME=SYSPLEX.OPERLOG) is attempted to be defined with “EHLQ=MY.PREFIX.IS.TOO.LONG”. Even though the EHLQ value is less than the maximum 33 characters, a log stream data set cannot be allocated with an overall name greater than 44 characters. In this example, the define request would fail with return code 8, reason code IXLRSNCODEBADEHLQ. This data set name is not valid because it is too long.
```
MY.PREFIX.IS.TOO.LONG.SYSPLEX.OPERLOG.suffix
```

HIGHOFFLOAD(80)

HIGHOFFLOAD(highoffload)

Specifies the percent value you want to use as the high offload threshold for the coupling facility space allocated for this log stream. When the coupling facility is filled to the high offload threshold point or beyond, system logger begins offloading data from the coupling facility to the DASD log stream data sets.

The default HIGHOFFLOAD value is 80%. You can specify the default in the following ways:

HIGHOFFLOAD(80)
HIGHOFFLOAD(0)
Omit the HIGHOFFLOAD parameter.

The value specified for HIGHOFFLOAD must be greater than the LOWOFFLOAD value.

LOWOFFLOAD(0)

LOWOFFLOAD(lowoffload)

Specifies the percent value you want to use as the low offload threshold for the coupling facility for this log stream. The low offload threshold is the point in the coupling facility, in percent value of space consumed, where system logger stops offloading coupling facility log data to log stream DASD data sets. The value of LOWOFFLOAD is the percent of log data system logger leaves in the coupling facility.

If you specify LOWOFFLOAD(0), which is the default, or omit the LOWOFFLOAD parameter, system logger uses the 0% usage mark as the low offload threshold.

The value specified for LOWOFFLOAD must be less than the HIGHOFFLOAD value.

WARNPRIMARY(NO_WARNPRIMARY)

WARNPRIMARY(NO)

WARNPRIMARY(YES)

Optional keyword input that specifies whether monitoring warning messages should be issued based on the log stream primary (interim) storage consumption above the HIGHOFFLOAD value.

The active primary TYPE=LOGR couple data set must be formatted at an HBB7705 (or higher) format level in order to specify WARNPRIMARY=YES. Otherwise, the request will fail with return code 8, reason code X’0839’. See LOGR parameters for format utility for more details.

If you omit the WARNPRIMARY parameter, the result will be the same as if you coded the NO_WARNPRIMARY option.

NO_WARNPRIMARY

Indicates that the WARNPRIMARY(NO) attribute should be used for the log stream unless the LIKE parameter is specified. If the LIKE parameter is specified, the WARNPRIMARY value will be copied from the referenced LIKE log stream entry.

NO

Indicates that the primary storage consumption monitoring warning messages will not be issued for the log stream.

YES

Indicates that log stream monitoring warning messages should be issued for the following conditions:

When the log stream primary (interim) storage consumption is 2/3 between the HIGHOFFLOAD value and 100% full (rounded down to the nearest whole number). This is called the log stream imminent alert threshold.
For example, assume the default value is used for the HIGHOFFLOAD percentage. That would mean a HIGHOFFLOAD value of 80 would be used, so the warning message would be triggered for this case at (2(100 - 80)/3 + 80) = 93%.
For a CF based log stream, when a 90% entry full condition is encountered.
When an interim (primary) storage full condition is encountered.

For more details on the messages and monitoring primary storage consumption, see Monitoring log stream interim storage consumption.

Note: This value can be overridden on the system level by system logger parameter options for IXGCNF keyword CONSUMPTIONMALERT(SUPPRESS).

LIKE(NO_LIKE)

LIKE(like_streamname)

Specifies the name of a log stream defined in the LOGR policy. The characteristics of this log stream (such as storage class, management class, high level qualifier and data class) will be copied for the log stream you are defining only if those characteristics are not explicitly coded on the referencing log stream. The parameters explicitly coded on this request, however, override the characteristics of the log stream specified on the LIKE parameter.

MODEL(NO)

MODEL(YES)

Specifies whether the log stream being defined is a model, exclusively for use with the LIKE parameter to set up general characteristics for other log stream definitions.

If you specify MODEL(NO), which is the default, the log stream being defined is not a model log stream. Systems can connect to and use this log stream. The log stream can also be specified on the LIKE parameter, but is not exclusively for use as a model.

If you specify MODEL(YES), the log stream being defined is only a model log stream. It can be specified only as a model for other log stream definitions on the LIKE parameter.

Programs cannot connect to a log stream name that is defined as a model (MODEL(YES)) using an IXGCONN request.

No log stream data sets are allocated on behalf of a model log stream.

The attributes of a model log stream are syntax checked at the time of the request, but not verified until a another log stream references the model log stream on the LIKE parameter.

DIAG(NO)

DIAG(YES)

Specifies whether or not dumping or additional diagnostics should be provided by System Logger for certain conditions.

If you specify DIAG(NO), which is the default, this indicates no special System Logger diagnostic activity is requested for this logstream regardless of the DIAG specifications on the IXGCONN, IXGDELET and IXGBRWSE requests.

If you specify DIAG(YES), this indicates that special Logger diagnostic activity is allowed for this log stream:

Informational LOGREC software symptom records (denoted by RETCODE VALU/H00000004) as well as other external alerts highlighting suboptimal conditions. See the section on enabling additional log stream diagnostics in z/OS MVS Diagnosis: Reference for more details.
When the appropriate specifications are provided on IXGCONN, IXGDELET, or IXGBRWSE requests by the exploiting application, further additional diagnostics may be captured. See the section on dumping on data loss (804-type) conditions in z/OS MVS Programming: Assembler Services Guide. for more details.

OFFLOADRECALL(YES)

OFFLOADRECALL(NO)

Indicates whether offload processing is to recall the current offload data set.

If you specify OFFLOADRECALL(YES), offload processing should recall the current offload data set.

If you specify OFFLOADRECALL(NO), offload processing should skip recalling the current offload data set and allocate a new one. Note that this option may cause any or all of the current offload data set to be wasted space on DASD once it is recalled. Care should be taken when using this option to size the data sets appropriately.

With OFFLOADRECALL(NO), system logger will request that allocation not wait on any ENQ serialization contention to be resolved, and will receive a class two type error (unavailable system resource), as described in Interpreting Error Reason Codes from DYNALLOC in z/OS MVS Programming: Authorized Assembler Services Guide.

ZAI(NO)

ZAI(YES)

ZAI(NO_ZAI)

Optional keyword that specifies whether the actual log stream data should be sent to the IBM zAware server.

The active primary TYPE=LOGR couple data set must be formatted at a z/OS V1R2 or later release level in order to specify ZAI(YES). Otherwise, the request will fail with return code 8, reason code X'0839'. See LOGR parameters for format utility for more details.

If you omit the ZAI parameter, the result will be the same as if you coded the NO_ZAI option.

If you specify ZAI(NO), it indicates that the log stream data will not be included in data sent from this z/OS IBM zAware log stream client to the IBM zAware server. NO is the default.

If you specify ZAI(YES), it indicates that the log stream data will be included in data sent to the IBM zAware server providing the z/OS IBM zAware log stream client is established. See Preparing for z/OS IBM zAware log stream client usage for more details on establishing and using z/OS IBM zAware log stream clients. Also refer to ZAIDATA keyword.

If you specify ZAI(NO_ZAI), it indicates that the default ZAI(NO) attribute should be used for the log stream unless the LIKE parameter is specified. If the LIKE parameter is specified, the ZAI value will be copied from the referenced LIKE log stream entry. Exercise care to ensure any newly defined log streams do not have the ZAI(YES) designation unless that is the absolute intention.

ZAIDATA('NO_ZAIDATA')

ZAIDATA('Xzaidata')

Optional keyword that provides the value, if any, to be passed to the IBM zAware server when the z/OS IBM zAware log stream client is established (refer to ZAI(YES) keyword specification). The ZAIDATA value must be between 1 and 48 characters long and enclosed in apostrophes.

The value you specify for the ZAIDATA keyword is defined by and must match the intended log data type and capabilities of the IBM zAware server. See Preparing for z/OS IBM zAware log stream client usage for more details on establishing and using z/OS IBM zAware log stream clients.

The active primary TYPE=LOGR couple data set must be formatted at z/OS V1R1 or later level in order to specify the ZAIDATA keyword option. Otherwise, the request will fail with return code 8, reason code X'0839'. See LOGR parameters for format utility for more details.

If you specify ZAIDATA('NO_ZAIDATA'), it indicates that a null value will be used for log stream ZAIDATA attribute. NO_ZAIDATA is the default.

If you specify ZAIDATA(Xzaidata), it indicates the value that will be passed to the IBM zAware server when the z/OS IBM zAware log stream client is established.

The Xzaidata value must be between 1 and 48 characters long and enclosed in apostrophes. The enclosing apostrophes are not counted as part of the value length. For example, assume the specification ZAIDATA('OPERLOG"). Even though 9 characters are specified within the keyword parenthesis, only 7 characters are within the delimiting apostrophes. So the resulting Xzaidata value length would be 7 for the string OPERLOG.

To code an apostrophe as part of the Xzaidata value, code 2 apostrophes where needed; it will result in 1 apostrophe and only count as 1 character in the value length. For example, assume the following specification of 26 characters within the keyword parenthesis ZAIDATA('OPERLOG,"somedata",END'). Because there are 24 characters within the delimiting apostrophes, and 2 apostrophes are coded twice within the string, the resulting Xzaidata value has 22 significant characters: OPERLOG,'somedata',END.

Valid characters are alphanumeric or national ($,#,@) characters, and any of the special (graphical) characters listed in Table 1. Lower case alphabetic characters will be folded to uppercase. Any other character will be converted into an EBCDIC blank (X'40').

Table 1. Valid special (graphical) characters
Character Name	Symbol	Hexidecimal (EBCDIC)
EBCDIC blank	<blank>	X'40'
Cent sign	¢	X'4A'
Period	.	X'4B'
Less than sign	<	X'4C'
Left parenthesis	(	X'4D'
Plus sign	+	X'4E'
Or sign	\|	X'4F'
Ampersand	&	X'50'
Exclamation point	!	X'5A'
Asterisk	*	X'5C'
Right parenthesis	)	X'5D'
Semicolon	;	X'5E'
Not sign	¬	X'5F'
Minus sign (hyphen)	-	X'60'
Slash	/	X'61'
Comma	,	X'6B'
Percent Sign	%	X'6C'
Underscore	_	X'6D'
Greater than sign	>	X'6E'
Question mark	?	X'6F'
Emphasis mark	`	X'79'
Colon	:	X'7A'
Apostrophe	'	X'7D'
Equal sign	=	X'7E'
Quote	"	X'7F'
Tilde	~	X'A1'
Left brace	{	X'C0'
Right brace	}	X'D0'
Backslash	\	X'E0'

If the resulting Xzaidata parameter value contains all X'40' (blanks), the ZAIDATA keyword will be treated as if NO_ZAIDATA has been specified.

Default: NO_ZAIDATA

If you omit the ZAIDATA parameter, the default will be used unless the LIKE parameter is specified. If the LIKE parameter is specified, the ZAIDATA value will be copied from the referenced LIKE log stream entry.

If you specify the ZAIDATA parameter, the value always overrides one specified on a model log stream used on the LIKE parameter.