Configuration restart example

Configuration restart files have been specified for the major nodes A, B, and C (CONFGA for major node A, CONFGB for major node B, CONFGC for major node C). Each major node is composed of four minor nodes (for example, major node A is composed of minor nodes A1, A2, A3, and A4). The following shows the minor nodes associated with each major node.

Major node A	Major node B	Major node C
A1 A2 A3 A4	B1 B2 B3 B4	C1 C2 C3 C4

Minor nodes B3 and B4 are to be initially active and the other minor nodes inactive.

Note: The initial status (active or inactive) can be specified for each minor node by coding the ISTATUS operand on the minor node definition statement.

The following chart shows the current contents of the configuration restart files for each major node.

CONFGA	CONFGB	CONFGC
empty	empty	empty

The VTAM® operator enters the following start options on the START command:

CONFIG=XX,NODELST=ABC

The CONFIG start option indicates which major nodes are to be activated when VTAM is started. In this example, configuration list ATCCONXX contains major nodes A and C. The NODELST start option specifies that the VSAM file ABC is to be used to record which major nodes are active in the network.

Because of the above start options:

VTAM activates major nodes A and C if it is able to open the NODELST file ABC.
VTAM records the activation of major nodes A and C in file ABC.

Then to activate major node B, the operator enters:

VARY NET,ACT,ID=B

VTAM activates major node B and records its activation in ABC. The VSAM NODELST file ABC now contains the following active nodes:

Major node A
Major node B
Major node C

VTAM also activates minor nodes B3 and B4 because ISTATUS=ACTIVE has been specified for them. Because B3 and B4 are defined as initially active, VTAM does not record the activation of B3 and B4 in CONFGB.

After the major nodes are active, the operator activates, deactivates, or modifies the status of minor nodes with VARY commands. Every time VTAM activates, deactivates, or modifies the status of a minor node, it records that action in the configuration restart file (if one exists) for the major node of which the minor node is a part.

VARY NET,ACT,ID=A2
VARY NET,ACT,ID=B3,LOGON=logapp1
VARY NET,INACT,ID=B3
VARY NET,ACT,ID=C4

As a result of the preceding commands, the status information stored in the configuration restart files can be represented as:

CONFGA	CONFGB	CONFGC
A2 active	B3 Status: LOGON B4 inactive	C4 active

If the network is now halted or if a failure occurs in the network, VTAM deactivates all the active major and minor nodes and closes the configuration restart files. The information needed to restore the network is in the VTAM definition statements and these files. When the VTAM operator restarts the network, start options can again be entered.

Start options specified	Major nodes restarted	Minor nodes restarted
CONFIG=XX,COLD	A and C	None
CONFIG=XX,WARM	A and C	A2 and C4
CONFIG=ABC,COLD	A,B, and C	B3 and B4
CONFIG=ABC,WARM	A,B, and C	A2, B3, and C4

Specifying CONFIG=XX,COLD or CONFIG=XX restores the network to its initial status while CONFIG=ABC,WARM restores the network to the status it had when VTAM stopped.

Note: COLD is assumed if neither COLD nor WARM is specified.

The operator can also specify another NODELST file:

CONFIG=ABC,WARM,NODELST=QRS

Or, the operator can continue using the one used before:

CONFIG=ABC,WARM,NODELST=ABC