MODIFY CSALIMIT command


>>-MODIFY-- --procname--,--CSALIMIT--=--+-value-----------------+-->
                                        '-(--value--+------+--)-'   
                                                    '-,--F-'        

   .-,--OPTION--=--TOTAL-----.   
>--+-------------------------+---------------------------------><
   '-,--OPTION--=--+-BELOW-+-'   
                   '-TOTAL-'

Abbreviations

Operand	Abbreviation
MODIFY	F
OPTION=BELOW	OPT=BELOW
OPTION=TOTAL	OPT=TOTAL

Purpose

Using the MODIFY CSALIMIT command, you can dynamically change the amount of common service area (CSA) storage that VTAM® is allowed to use.

Note:

You can use the MODIFY VTAMOPTS command (CSALIMIT and CSA24 operands) to perform the same function as this command. Use CSALIMIT for OPTION=TOTAL and CSA24 for OPTION=BELOW.
MODIFY CSALIMIT may not function if VTAM's available CSA is exhausted to the point that the LPBUF buffer pool cannot expand.
Unless CSA24 is indicated, all references to CSA mean CSA plus ECSA.

Operands

procname

The procedure name for the command. If procname in the START command was specified as startname.ident, where startname is the VTAM start procedure and ident is the optional identifier, either startname.ident or ident can be specified for procname.

If procname in the START command was startname, startname must be specified for procname.

CSALIMIT

The value operand specifies the maximum amount of common service area (CSA) storage to be used by VTAM and whether VTAM is to be forced to use that value (F). The actual amount of storage used by VTAM for the CSA can be less than or equal to the CSALIMIT. Use the DISPLAY BFRUSE command to display the current CSALIMIT setting, VTAM CSA usage, system CSA limit, and system CSA storage remaining.

CSALIMIT=value

Specifies the maximum amount of CSA storage to be used by VTAM. The value operand can be specified in any of the following forms:

0

When OPTION=BELOW, specifies that no limit is enforced on the amount of CSA used by VTAM. When OPTION=TOTAL, specifies the maximum amount of CSA used by VTAM is to be set to the system CSA limit. To find out what the system CSA limit is for your system, use the DISPLAY BFRUSE command.

n or nK

n is a decimal integer that specifies VTAM's CSA usage limit in units of K (1024 bytes). For example, if CSALIMIT=4 or CSALIMIT=4K is specified, a CSA limit of 4096 is assigned. The maximum value that can be specified is 2097152K bytes.

If the value specified for n is not a multiple of 4, it is rounded to the next page-size multiple (4K bytes).

Note:

If the number you code is greater than the system CSA limit (of all CSA + ECSA defined in the system) CSALIMIT is set to 90% of the system CSA limit (which is the default). If the value specified is less than 25 MB and the ,F modifier is used on the command, a message will be issued. See the DISPLAY BFRUSE command for information about displaying the current CSALIMIT setting, VTAM CSA usage, system CSA limit, and available system CSA.
If CSALIMIT is specified (but without the ,F modifier) and VTAM CSA usage reaches this specified CSALIMIT value with 25% or more of system CSA storage remaining available for use, a warning message will be issued. VTAM will continue to run until only 25% of CSA storage remains available for use. If you want to prevent VTAM from using additional CSA beyond the specified CSALIMIT value, issue a MODIFY CSALIMIT or MODIFY VTAMOPTS,CSALIMIT command with the required CSALIMIT value and the ,F operand specified.
If the number specified is greater than the available CSA, no limit is enforced.

qM

q is a decimal integer that specifies VTAM's CSA usage limit in units of M (1048576 bytes, or 1024K bytes). For example, if CSALIMIT=4M is specified, a CSA limit of 4194304 bytes is assigned. The maximum value that can be specified is 2048M.

Note: If the number specified is greater than the available CSA, no limit is enforced.

CSALIMIT=(value,F)

Forces the specified value, n, nK, or qM, to be used as the CSA usage limit, regardless of how much CSA storage is currently allocated to VTAM. If VTAMs current CSA value is greater than a newly specified CSALIMIT value, all subsequent CSA requests by VTAM components are rejected until the current CSA value falls below the CSALIMIT value.

If F is not specified, and the operator has specified a limit smaller than the amount of CSA storage currently allocated to VTAM, a request to change the CSA limit will be allowed if there is more than 25% of the system CSA storage available for use. If F is specified, the request to change the CSA will be successful but VTAM will not use more CSA than the CSALIMIT specified.

Attention: If a CSA limit is specified that is too low and the operator forces this limit to take effect (by using F), the operator is prevented from using VTAM commands until the CSA usage falls below the specified limit, because CSA storage is needed to process all VTAM operator commands except HALT CANCEL. If the CSA usage does not fall below the specified CSA limit, VTAM must be canceled and restarted with a more appropriate CSALIMIT value specified.

OPTION

Specifies the area to be limited.

OPTION=TOTAL: Designates the maximum amount of 24-bit or 31-bit addressable CSA storage VTAM can use.
OPTION=BELOW: Specifies that the MODIFY CSALIMIT command designates the maximum amount of 24-bit addressable storage VTAM can use. OPTION=BELOW corresponds to the CSA24 start option.
Note: OPTION=BELOW limits only the amount of explicitly requested 24-bit addressable storage (for example, GETMAIN LOC=BELOW). If VTAM is not specific about the location of the storage desired (for example, GETMAIN LOC=ANY), and the operating system returns 24-bit addressable storage, that storage is not subject to OPTION=BELOW limitations. Instead, it is treated as 31-bit addressable storage in DISPLAY command output.