LFAREA

LFAREA = {xM | xG | xT | x%}
         {(xM | xG | xT | x% [,INCLUDE1MAFC(YES|NO)])}
         {( [1M=(a [,b]) | 1M=(a% [,b%])]
            [,2G=(a [,b]) | ,2G=(a% [,b%])]
            [,PROMPT | ,NOPROMPT]
            [,INCLUDE1MAFC(YES|NO)]
           )}
The LFAREA parameter specifies the maximum amount of online real storage Start of changebelow 4 TBEnd of change available at IPL that can be used to satisfy fixed 1 MB and 2 GB page requests. The xM, xG, xT, and x% syntax form specifies the maximum amount of 1 MB pages, and the 1M= and 2G= syntax form specifies the maximum amount of 1 MB and 2 GB pages. The two syntax forms cannot be combined. Each syntax specification uses a different formula for calculating percentage requests and the system limit, as described in Request handling for the LFAREA system limit and Request handling for insufficiently contiguous online real storage.
Notes: Start of change
  1. Specifying LFAREA for fixed 1 MB pages does not reserve an amount of real storage to be used exclusively for fixed 1 MB page requests. It simply specifies the target cap for the most fixed 1 MB page requests that can be satisfied for this system.
  2. All online real storage above 4 TB is part of the 2G LFAREA in addition to what is specified by the LFAREA keyword. For example, an 8 TB system with LFAREA=(1M=1024,2G=512) results in a 1 MB LFAREA of size 1 GB, and a 2 GB LFAREA of size 5 TB (1TB for the specified 512 2 GB pages. This includes all of the real storage in the 4 TB minus 8 TB range).
End of change

In the following descriptions, 2 GB is equal to a decimal value of 231, or 2147483648, and 4 GB is equal to a decimal value of 232, or 4294967296.

Value range: The following value ranges apply to the value specified on the LFAREA parameter. The maximum values that can be specified for the LFAREA are described in Request handling for the LFAREA system limit.
xM or xG or xT
Specifies the maximum amount of online real storage that can be used to satisfy fixed 1 MB page requests. Up to six decimal digits can be specified for x: xM specifies the amount is in megabytes; xG specifies the amount is in gigabytes; xT specifies the amount in terabytes. A specification of 0M, 0G, or 0T results in the system using no real storage to satisfy fixed 1 MB page requests for the life of the IPL.
x%
Specifies the maximum amount of online real storage that can be used to satisfy fixed 1 MB page requests, as a percentage of the total online real storage at IPLStart of change up to 4 TBEnd of change. Up to two digits can be specified. The percentage is calculated as (x% * online real storage at IPLStart of change up to 4 TBEnd of change) minus 2G. The maximum percentage that can be specified is 80%. A specification of 0% results in no successful fixed 1 MB page requests.
1M=(a)
Specifies the maximum number of 1 MB pages of that can be used to satisfy fixed 1 MB page requests. Up to eight decimal digits can be specified for a. A specification of 1M=(0,0) results in the system using no real storage to satisfy fixed 1 MB page requests for the life of the IPL.
1M=(a,b)
Specifies the maximum number of 1 MB pages that can be used to satisfy fixed 1 MB page requests. Up to eight decimal digits each can be specified for a and b. The value that is specified for a is the target number of pages, and the value that is specified for b is the minimum number. The system attempts to meet the request at or as near as possible up to the target number, but at no less than the minimum number. The value that is specified for b must be less than or equal to the value specified for a, and can be zero. A specification of 1M=(0,0) results in the system using no real storage to satisfy fixed 1 MB page requests for the life of the IPL. When the LFAREA parameter is processed, no additional amounts of storage are reserved later in an attempt to reach the target. Both a value and a percentage, such as 1M=(a,b%) or 1M=(a%,b), cannot be specified.
1M=(a%)
Specifies the maximum amount of online real storage that can be used to satisfy fixed 1 MB page requests, as a percentage. Up to two digits can be specified. The storage amount is calculated as a% * Start of change((online real storage at IPL up to 4 TB) minus 4 GB), End of change rounded down to the nearest 1 MB boundary. The maximum percentage that can be specified is 80%. A specification of 1M=(0%) results in the system using no real storage to satisfy fixed 1 MB page requests for the life of the IPL.
1M=(a%,b%)
Specifies the maximum amount of online real storage that can be used to satisfy fixed 1 MB page requests, as a percentage. Up to two digits each can be specified for a% and b%. The value that is specified for a% is the target amount, and the value that is specified for b% is the minimum amount. The system attempts to satisfy the request at or as near as possible up to the target amount, but at no less than the minimum amount. The percentages are calculated as percent * Start of change((online real storage at IPL up to 4 TB) minus 4 GB)End of change, rounded down to the nearest 1 MB boundary. The maximum percentage that can be specified for a% is 80%. The value that is specified for b% must be less than or equal to the value for a%, and can be zero. A specification of 1M=(0%,0%) results in the system using no real storage to satisfy fixed 1 MB page requests for the life of the IPL. When the LFAREA parameter is processed, no additional amounts of storage are reserved later in an attempt to reach the target. Both a value and a percentage, such as 1M=(a,b%) or 1M=(a%,b), cannot be specified.
Start of change2G=(a)End of change
Start of changeStart of changeSpecifies the number of 2 GB pages of online real storage below 4 TB to reserve in the large frame area. Up to eight decimal digits can be specified for a. A specification of 2G=(0) results in zero 2 GB pages being reserved below 4 TB. Each 2 GB page is placed only in a 2 GB area of contiguous real storage on a 2 GB boundary, which means that enough 2 GB areas of contiguous online storage on 2 GB boundaries must be available at IPL for the number of 2 GB pages requested. In addition to what is specified, all real storage above 4 TB is also included in the large frame area as 2 GB frames.End of changeEnd of change
Start of change2G=(a,b)End of change
Start of changeStart of changeSpecifies the number of 2 GB pages of online real storage below 4 TB to reserve in the large frame area. Up to eight decimal digits each can be specified for a and b. The value that is specified for a is the target number of pages, and the value that is specified for b is the minimum number. The system attempts to satisfy the request at or as near as possible up to the target number, but at no less than the minimum number. The value that is specified for b must be less than or equal to the value for a, and can be zero. A specification of 2G=(0,0) results in zero 2 GB pages being reserved below 4 TB. When the LFAREA parameter has been processed, no additional amounts of storage are reserved later in an attempt to reach the target. Both a value and a percentage, such as 2G=(a,a%) or 2G=(a%,a) cannot be specified. Each 2 GB page is placed only in a 2 GB area of contiguous real storage on a 2 GB boundary, which means that enough 2 GB areas of contiguous online storage on 2 GB boundaries must be available at IPL for at least the minimum number of 2 GB pages requested. In addition to what is specified, all real storage above 4 TB is also included in the large frame area as 2 GB frames.End of changeEnd of change
Start of change2G=(a%)End of change
Start of changeStart of changeSpecifies the amount of online real storage below 4 TB to reserve in the large frame area for 2 GB pages, as a percentage. Up to two digits can be specified for a. The storage amount is calculated as a% * ((online real storage at IPL up to 4 TB) minus 4 GB), rounded down to the nearest 2 GB boundary. The maximum percentage that can be specified is 80%. A specification of 2G=(0%) results in zero 2 GB pages being reserved below 4 TB. Each 2 GB page is placed only in a 2 GB area of contiguous real storage on a 2 GB boundary, which means that enough 2 GB areas of contiguous online storage on 2 GB boundaries must be available at IPL for the amount of 2 GB pages requested. In addition to what is specified, all real storage above 4 TB is also included in the large frame area as 2 GB frames.End of changeEnd of change
Start of change2G=(a%,b%)End of change
Start of changeStart of changeSpecifies the amount of online real storage below 4 TB to reserve in the large frame area for 2 GB pages as a percentage. Up to two digits each can be specified for a% and b%. The value that is specified for a% is the target amount, and the value that is specified for b% is the minimum. The system attempts to satisfy the request at or as near as possible up to the target amount, but at no less than the minimum amount. The percentages are calculated as percent * * ((online real storage at IPL up to 4 TB) minus 4 GB), rounded down to the nearest 2 GB boundary. The maximum percentage that can be specified for a% is 80%. The value that is specified for b% must be less than or equal to the value for a%, and can be zero. A specification of 2G=(0%,0%) results in zero 2 GB pages being reserved below 4 TB. When the LFAREA parameter has been processed, no additional amounts of storage are reserved later in an attempt to reach the target. Both a value and a percentage, such as 2G=(a,b%) or 2G=(a%,b), cannot be specified. Each 2 GB page is placed only in a 2 GB area of contiguous real storage on a 2 GB boundary, which means that enough 2 GB areas of contiguous online storage on 2 GB boundaries must be available at IPL for at least the minimum amount of 2 GB pages requested. In addition to what is specified, all real storage above 4 TB is also included in the large frame area as 2 GB frames.End of changeEnd of change
PROMPT | NOPROMPT
Specifies whether the system prompts for respecification of the LFAREA parameter when the request cannot be satisfied. The default is PROMPT, which specifies for the system to prompt when either the 1M= or 2G= request cannot be satisfied. The value NOPROMPT specifies for the system to ignore the LFAREA request when either or both of the 1M= and 2G= requests cannot be satisfied, and to instead have zero 1 MB pages and zero 2 GB pages that can be used to satisfy fixed 1 MB and 2 GB page requests.
INCLUDE1MAFC(YES|NO)
Specifies whether the 1 M LFAREA specification is included in the available frame count (RCEAFC). With z/OS® V2R3, the INCLUDE1MAFC specification is ignored. The 1 M LFAREA specification is always included in the available frame count (RCEAFC).
YES
Specifies that the 1 M LFAREA specification is included in the available frame count. This is the default and the only accepted value.

For compatibility with applicable releases before z/OS V2R2, you can also specify INCLUDE1MAFC(YES) as INCLUDE1MAFC.

NO
Specifies that the 1 M LFAREA specification is not included in the available frame count.

This value is always ignored.

Default: INCLUDE1MAFC(YES).
Notes:
  1. Application programs can check the RCEINCLUDE1MAFC bit to determine if INCLUDE1MAFC(YES) is in effect, regardless of z/OS release.
  2. Application programs that use the STGTEST SYSEVENT must be assessed to determine if any changes need to be made. The STGTEST event returns information about the amount of storage available in the system, which includes the LFAREA. .