IBM Session Manager Implementation

194 IBM Session Manager Implementation

Figure 7-2 ITSO Session Manager environment

7.2 Configuring Session Manager to use VTAM Generic

Resources

In this section we configure Session Manager to use VTAM Generic Resources.

7.2.1 What is a VTAM Generic Resource

The generic resources function allows the assignment of a generic resource

name to a group of active application programs that all provide the same

function. The generic resource name is assigned to multiple active application

programs simultaneously, and VTAM automatically distributes sessions among

these application programs rather than assigning all sessions to a single

resource. Thus, session workloads in the network are balanced. Session

distribution is transparent to end users; an LU initiates a logon request using the

SYSPLEX WTSCPLX1

VTAM applid ISZSM66

VTAM generic ISZSMGR

Host wtsc66 port 9993

Telnet Server

LOCALNODE ISZLNK66

ISM 1.200A on SC66

TCPIP

VTAM 6.1.5

VTAM applid ISZSM48

VTAM generic ISZSMGR

Dynamic DVIPA port 9993

Telnet Server

LOCALNODE ISZLNK48

ISM 1.200A on SC48

TCPIP

VTAM 6.1.5

VTAM applid ISZSM53

VTAM generic ISZSMGR

Host wtsc53 port 9993

Telnet Server

LOCALNODE ISZLNK53

ISM 1.200A on SC53

TCPIP

VTAM 6.1.5

VTAM applid ISZSM523

VTAM generic ISZSMGR

Dynamic DVIPA port 9993

Telnet Server

LOCALNODE ISZLNK52

TCPIP

VTAM 6.1.5

ISM 1.200A on SC52

Chapter 7. Sysplex Environment 195

generic resource name and need not be aware of which particular application

program is actually providing the function.

The generic resources function also increases application program availability,

as each active application program that uses a given generic resource name (a

generic resource member) can back up other generic resource members. Thus,

no single application program is critical to resource availability. When a generic

resource member fails, an LU can reinitiate its session using the same generic

resource name. VTAM resolves the session initiation to one of the other generic

resource members. Because the user is unaware of which generic resource

member is providing the function, the user is less affected by the failure of any

single generic resource member.

In the same way, an application program can be added as a generic resource

member and accessed using the same generic resource name. Because the

user is unaware of which generic resource member is providing the function, an

application program can be added as a generic resource member with little or no

impact to the application user. At the same time, the additional application

program provides an immediate improvement in performance and availability

since the workload is now shared by an additional application program.

Use of generic resources requires a coupling facility structure. Refer to the

Communications Server SNA Network Implementation Guide, SC31-8777, for

specific information on VTAM Generic Resources.

The only parameter the user needs to specify to request Session Manager to

register as a VTAM Generic Resource is the GENERICACB generic-acbname

parameter on the SYSTEM statement. A common (or generic) ACB name can be

specified in a syspled system where a Session Manager system is run on each

clone. Session Manager opens the acbname

specified by the ACB parameter

and also the generic-acbname. Users should sign on using the

generic-acbname, and the sysplex will attempt to balance the signons across the

clones. When necessary, users can sign on to a particular Session Manager

system by using the ACB parameter acbname.

A display of the VTAM ISTGENERIC structure as in the following example will

indicate which VTAMs are using the structure.

196 IBM Session Manager Implementation

D XCF,STR,STRNAME=ISTGENERIC

IXC360I 18.16.37 DISPLAY XCF 920

STRNAME: ISTGENERIC

STATUS: ALLOCATED

TYPE: SERIALIZED LIST

POLICY INFORMATION:

POLICY SIZE : 24576 K

POLICY INITSIZE: N/A

POLICY MINSIZE : 0 K

FULLTHRESHOLD : 80

ALLOWAUTOALT : NO

REBUILD PERCENT: N/A

DUPLEX : DISABLED

PREFERENCE LIST: CF03 CF06

ENFORCEORDER : NO

EXCLUSION LIST IS EMPTY

ACTIVE STRUCTURE

----------------

ALLOCATION TIME: 06/11/2004 15:05:07

CFNAME : CF03

COUPLING FACILITY: 002084.IBM.02.000000026A3A

PARTITION: 1E CPCID: 00

ACTUAL SIZE : 24576 K

STORAGE INCREMENT SIZE: 256 K

PHYSICAL VERSION: BB5AAB3B 5C771E85

LOGICAL VERSION: BB5AAB3B 5C771E85

SYSTEM-MANAGED PROCESS LEVEL: 8

XCF GRPNAME : IXCLO00F

DISPOSITION : DELETE

ACCESS TIME : 1800

MAX CONNECTIONS: 32

# CONNECTIONS : 16

CONNECTION NAME ID VERSION SYSNAME JOBNAME ASID STATE

---------------- -- -------- -------- -------- ---- ----------------

USIBMSC_SC04M 0E 000E00E5 SC04 VTAM44 001B ACTIVE

USIBMSC_SC42M 08 00080884 SC42 VTAM44 001B ACTIVE

USIBMSC_SC43M 0F 000F00AE SC43 VTAM44 001C ACTIVE

USIBMSC_SC47M 10 001000A2 SC47 VTAM44 001B ACTIVE

USIBMSC_SC48M 0B 000B01D6 SC48 VTAM44 001B ACTIVE

USIBMSC_SC49M 06 000609BD SC49 VTAM44 001B ACTIVE

USIBMSC_SC50M 05 00051388 SC50 VTAM44 001B ACTIVE

USIBMSC_SC52M 07 00070A23 SC52 VTAM44 001B ACTIVE

USIBMSC_SC53M 01 00010A5A SC53 VTAM44 001B ACTIVE

USIBMSC_SC54M 03 000309C6 SC54 VTAM44 001B ACTIVE

USIBMSC_SC55M 02 000209C5 SC55 VTAM44 001B ACTIVE

USIBMSC_SC61M 04 000409B1 SC61 VTAM44 001C ACTIVE

USIBMSC_SC62M 0A 000A117C SC62 VTAM44 001C ACTIVE

USIBMSC_SC66M 0D 000D00E7 SC66 VTAMBUDI 001C ACTIVE

USIBMSC_SC67M 0C 000C0131 SC67 VTAM44 001B ACTIVE

USIBMSC_SC69M 09 000914BD SC69 VTAM44 001B ACTIVE