Tuning Distributed FileManager Startup Parameters in System PARMLIB

You can tune the startup parameters for DFM to fit your installation's performance requirements. These parameters are contained in PARMLIB member DFM00 (for example, SYS1.PARMLIB(DFM00)). If DFM00 needs to be installed in PARMLIB on your system, you can copy system SAMPLIB member DFM00 (for example, SYS1.SAMPLIB(DFM00)). DFM00 can also be found in DFM00.

The parameters shown in Table 1 fall into categories related to either performance tuning or data set definition defaults.

Table 1. Tunable Parameters in DFM00
Parameter	Description	Default	Range
CLOSE_CHECK_INTV	Time interval (in seconds) to wait between searches of the Open PDSE queue for data sets to close	0	0—100
DEFER_CLOSE_TIME	Time interval (in seconds) to wait before closing a PDSE data set after a DDM close command has been processed	0	0—100
LOCK_RETRY	Number of lock conflict retries	3	1—100
LOCK_WAIT_INTV	File lock wait interval in seconds	20	1—100
MAX_AGENT_TSKS	Number of agents supported	5	1—100
MAX_CONV_LOCK	Maximum locks on a file per agent	5	1—100
SEND_BUFFER_THRESHOLD	Maximum number of buffers between APPC SEND verb completions	100	1—1,000
LOGICAL_CACHE	Cache limit for stream files	1,024	1—2,047
CCSID	Coded character set identifier (CCSID) for DFM	0	0—65,535
PRIMARY	Data set space allocation in records (non-SMS only)	100	1—2GB
SECONDARY	Data set space allocation in records when PRIMARY space is exhausted (non-SMS only)	50	0—2GB
STREAM_LRECL	Logical record length for stream files	8,196	0—32,760
UNIT	Device type where non-SMS data sets are created, see VOLUME	SYSALLDA	N/A
VOLUME	DASD volume serial number for non-SMS data set creation	None	N/A
RESTRICT_START	Startup command in the PARMLIB DFM00 member	Yes	Yes or No