Storage estimate worksheets

This appendix describes how to estimate the virtual storage required to run z/OS® Communications Server on the z/OS operating system. From the following list, select and review the applicable worksheets:

APPN
- Interchange node (ICN) or network node (NN)
- Migration data host (MDH) and end node (EN)
Subarea
- Communication management configuration (CMC)
- Data host (DH)

This appendix also contains an APPL EAS storage estimate table; see APPL EAS storage estimates.

Users of APPC will notice an increase in storage utilization because VTAM® will now allocate an additional 160 bytes (for a mini-VIT trace) per control block representing a single APPC conversation. See z/OS Communications Server: SNA Diagnosis Vol 2, FFST Dumps and the VIT for information about VTAM Internal Trace (VIT) tracing.

Users of APPN will notice an increase in storage utilization because VTAM will now allocate additional storage for TRS (Topology and Routing Services) topology traces. To calculate the increase, add the following:

For the TRS topology trace where topology record deletions are recorded, one to ten 4K pages of storage will be allocated. One 4K page will be allocated at VTAM initialization. When that page is full of trace entries, another page will be allocated, up to a maximum of ten 4K pages.
For the NDREC (node record) traces, 110 bytes of storage will be allocated for each node in the network or sub-network.
- In a network node, this would include:
  - All network nodes
  - All served end nodes (the network node has acted as the NNS or DLUS for the end node)
  - All virtual nodes
- In an end node, this would include:
  - Network nodes with which the end node has established connections
  - End nodes with which the end node has established connections
  - Virtual nodes through which the end node has established connections
For the TGREC (TG record) traces, 180 bytes of storage will be allocated for each TG in the network or subnetwork.
- In a network node, this would include:
  - Two TGs for every link between network nodes (one TGREC represents the connection in one direction and one TGREC represents the connection in the reverse direction)
  - One TG for every connection that a VTAM end node served by this network node server has with any other network node, end node, or virtual node
  - One TG for every connection that a DLUR end node served by this DLUS has with any other network node, end node, or virtual node
  - Two TGs for every connection between network nodes and virtual nodes (one TGREC represents the connection in one direction and one TGREC represents the connection in the reverse direction)
  - One TG for every connection to an adjacent end node or an adjacent DLUR end node
- In an end node, this would include:
  - One TG for every link from this end node to any other network node, end node, or virtual node.