Planning FEPI storage

FEPI does not require any additional MVS™ storage beyond that recommended for basic CICS®. As for dynamic storage, the storage used by FEPI is allocated exclusively from CDSA and ECDSA; CDSA usage is only that required to support VTAM® processing. The following information allows you to estimate the storage requirements of a particular FEPI configuration.

Table 1. Dynamic storage requirements (in bytes)
Item ECDSA CDSA
Basic 80K
For each node 288 180
For each node that is currently available for communication 192
For each target 236
For each pool 272
+ 64 x (number of nodes in pool)
+ 64 x (number of targets in pool)
For each property set 176
For each connection (note 1) 432 if using data stream data
688 if using formatted data
For each connection that is currently available for communication 384
+ additional value from Table 2 if using formatted data
For each current conversation 128
For each command in progress 2.5K
+ size of user data (Note 2)
Notes:
  • 1. The number of connections is (number of nodes in pool) x (number of targets in pool) for each pool.
  • 2. This is the data that is to be sent and received, or used for defining resources. If global user exits are used, twice the data size is needed; similarly if journaling is used.

For each connection that is currently available for communication and that uses formatted data, additional ECDSA storage is required; the amount depends on the device type and capabilities defined, as shown in Table 2.

Table 2. Connection storage requirements (in bytes) by device type and function
Device type Basic Additional for color support Additional for extended data stream support Maximum
327x model 2 3840 1920  5760 11520
327x model 3 5120 2560  7680 15360
327x model 4 6880 3440 10320 20640
327x model 5 7128 3564 10692 21384

You should add some contingency (say 10%) to your final estimate.

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