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© 2012 IBM Corporation

Simplify IMS System Management

Isabelle BRUNEEL


Topics

� System definition

– DRD / Repository

– ETO Support to simplify exits, not only ETO exits

– What are the Online parameters of IMS ?

� System management

– ACBLIB management

– Type 2 commands

� Optimize restart

– With Batch management

– With External Subsystems such as DB2

� Queue management

– DFSQSPC0 / DFSQSSP0

– QCF V3

– Transaction expiration


System Definition: Without Dynamic Resource Definition

� Each IMS system must have a definition of its resources

– Databases, Transactions, Programs and Fastpath Routing Codes• The “MODBLKS resources”

– Created in the MODBLKS dataset by the IMS System Definition process• Stage 1 input (Assembler Macros) can be very large and requires careful management

� The definitions can be changed with Online Change, but:

– Requires the complete set of resource definitions to be re-built every time• Even for a change of one attribute of one resource!

– Requires all system processing to be quiesced for the MODBLKS library switch• Impacts service availability


System Definition: Dynamic Resource Definition (DRD)

� When DRD is enabled, resources need only ever be created once

– Kept in a Resource Definition Dataset (RDDS)

� Resources are NOT defined in IMS System Definition

– Stage 1 input – especially with ETO – will be very small

– IMS System Definition process will rarely be required …

– … and will be much quicker

� Resources are updated at a SPOC with UPDATE commands, added with CREATE

commands, and deleted with DELETE commands

– No impact on availability of unchanged resources

– All resources written to oldest RDDS at next system checkpoint

� Resource definitions are portable between RDDSs

– Using EXPORT and IMPORT commands

DRD was introduced with IMS

Version 10


System Definition: DRD Overview

IMS System

Definition

Process

IMS

IMS.MODBLKS

IMPORT

command

CREATE,

DELETE,

UPDATE,

EXPORT,

IMPORT

commands

Resource

Definition

Dataset

System Resource

Definition

Datasets

(RDDS)

EXPORT

command

Automatic

export

Control BlocksDDIRsPDIRsSMBsRCTEs

Operations

Manager

Interface

Non-system

RDDS

EXPORT

command

IMPORT

command

DRD was introduced in

IMS 10

Automatic

Import (cold start)


System Definition: Repository Function Architecture Overview

Operations

Manager

(OM)

Structured

Call

Interface

Resource

Manager

(RM)

IMS Control Region

Repository

Server

(RS)

SCI SCI SCI

SCI

SCI

XCF

X

C

F

Batch ADMIN

Utility

(FRPBATCH)

Repository

Server

Commands

(z/OS Modify)

Audit L

og

X

C

F

CSLURP10 /

CSLURP20

X

C

F

RDDS

RS Catalog

Repository

Index Member

Primary/Secondary

IMSRSC Repository

Index Member

Primary/Secondary/Spare

Runtime

Definitions

Stored

Definitions

Stored

Definitions

z/OS Modify

SPOC


System Definition: Current ETO, OTMA, NDM EXIT STATUS

Back to the list of larger customers’ set of used IMS exits .. :

� DFSLGNX0 (Logon Exit)

� DFSSGNX0 (Signon Exit)

� DFSLGFX0 (Logoff Exit)

� DFSGMSG0 (Good morning message Exit)

� DFSINSX0 (Destination Creation Exit)

� DFSINTX0 (Initialization Exit)

� DFSNDMX0 (Non Discardable Message Exit)

� DFSYPRX0 (Destination Resolution Exit)

� DFSYDRU0 (User Data Formatting Exit)

� DRU0MQS (DFSYDRU0 for MQ OTMA Client Exit)

� DRU0HWS (DFSYDRU0 for ICON OTMA Client Exit)

� DFSBSEX0 (Build Security Environment Exit)

… Nothing to do with ETO feature …

�Above Exits require customization & maintenance

�Any business change implies a change to the above exits, and so:�Assembler Code to be written�IMS to be recycled


System Definition: Free yourself from IMS exits with ETO/Support Solution

� Get rid of IMS exits management and use a standard solution• avoid error prone exits coding• dedicate people to other more challenging activities• allow also a beginner to do the job• no need to know IMS control blocks structure and contents

� No need to have Assembler skill • or to look for external assembler knowledge (current and/or future)

� Continuous availability• Improve IMS services • no need to re-cycle IMS to carry on new definitions and/or updates

Apply to all IMS Members of an IMSPlex environment

� Allow dynamic deployment of new requests instead of waiting for IMS exits to be

coded, tested, brought in pre-production – production environments (and IMS

recycled)• Real cases show new definitions done in a matter of minutes instead of days or weeks


System Definition: ETO/S Solution Primary screen


System Definition: ETO/Support solution behaviour

� IMS ETO/S definitions done online via IZTRAN

– or via batch load pgm through a series of IMS ETO/S control statements

– Has also the possibility to read IMS Sysgen Terminal definitions and Descriptors to

populate IMS ETO/S Repository

� IMS ETO/S definitions saved in a repository

– Could be an IMS DB

– or a VSAM ds

– Repository saved via standard DB• It can be shared as a shareable DB• or VSAM backup procedure

– Or unloaded, to produce the Batch sysin control statements used as input for the batch

load pgm

� ETO/S LoadLib required in IMS CTRL Steplib

– And in the MPP where IZTRAN runs

� ETO/S repository loaded in ECSA when IMS Control Region starts

– ETO/S will send IZT msg’s during IMS start-up

– ECSA refreshed dynamically via APPC transaction or via batch job


SHISAM

ETO Support DBETO Support DB�Recoverable using standard IMS

utilities

�Updatable

�online with IZTRAN

�in batch by program IZTUD1U0

ECSA

IMS1 IMS2

ETO Support Tables

IMS3

ECSA

ETO

Functions

ETO

Functions

ETO

Functions

MVS1 MVS2

IZTRANIZTUD1U0

ETO Support TablesETO Support Tables�Loaded at IMS Startup (DFSINTX0)

�Refreshed on demand

�Batch refresh

for single system only

�Via IZTRAN

on all systems, using APPC

System Definition: IMS ETO/Support Architecture


System Definitions: What are the active IMS parameters ?

� Through a monitor such Omegamon : 3270 interface for IMS ( CUA )


Parameters Management with Configuration Manager

� Enhanced parameter listing and search

– Semantic search: finds parameters and members based on keywords; identifies missing

parameters and members

– Listing of PROCLIB members that are active on a given system

– Edit history for all members

� Enhanced ISPF edit session that provides:

– Checking of parameter syntax

– Ability to insert parameters from a model

– Context sensitive help for all parameters

– Retains many ISPF edit functions

– Does not alter or modify the member in anyway (unless you explicitly add or modify

parameters)

– Allows you to back up members before saving them

– In the future will be extended to perform checking of entire PROCLIBs


System Management: Need help to clean the ACBLIB ?

� LIU Library Integrator Utility Consistency checker

DBDLIB PSBLIB

RDDS

DFSMDAACBLIB

MODBLKS

RECON

Controlstatements

INPUT

Co

ns

iste

nc

yc

he

ck

er

DBD Report

PSB Report


System Management: Don’t trust a DBD ?

� LIU Library Integrator Utility DBD/PSB/ACB compare or reversa

� The DBD/PSB/ACB Compare utility reports the differences between two control blocks (DBDs, PSBs, or ACBs), of the same type or different types, that have the same name but reside in different IMS libraries.

� The DBD/PSB/ACB Reversal utility converts DBD, PSB, and ACB control blocks back into IMS DBDGEN and IMS PSBGEN utility control statements.

DBDLIB1 DBDLIB2

ACBLIB2

PSBLIB2PSBLIB1

ACBLIB1

Controlstatements

INPUT

AC

B/D

BD

/PS

B c

om

pa

re

an

d re

ve

rsa

l

Block level

Source level


Type-2 commands

� To be entered only from the OM API ( TSO SPOC or any user program using OM API, including REXX and Batch , and IMS Connect Operator Console)

� All Type-1 have an equivalent in type-2

� Some type2 have no equivalent in TYPE1 – ( UPD TRAN NAME(*) SET LOCK(ON) (SCHED) and /LOCK TRAN tranname ) – Initiate OLR

� IMS Connect WTO commands have type2 equivalent in IMS V12 :– QUERY IMSCON xxx– UPDATE IMSCON

� Output is in XML tag structure.– Easier to use, sort and parse

� New features in IMS V12 (Dynamic Full Function Database Buffer Pools) only withtype-2 commands


Optimize Restart with Batch management

� IMS Program Restart Facility– automates the restart of abended BMP regions– intercepts and writes checkpoint records to two small data sets.

• datasets deleted when the batch job completes successfully.

• if abend, datasets remains in place, and are used to restart the job.

– in a data sharing IMSPlex environment, allows a BMP to be restarted using a different IMS system.– bypass Checkpoint Processing, which throttles the frequency of application checkpoints. This can

reduce logging and improve batch job elapsed times.– flag non-zero return code as an abend, which causes PRF to treat a batch job with a non-zero return

code as an abend, ensuring that the job is restarted properly.– provides an option to hold and restart a BMP through operator commands – without actually stopping

the job.

� IMS Batch Backout Manager– automates the restart of abended DLI batch jobs– dynamically allocates an interim batch SLDS for the log close – closes the interim batch SLDS – dynamically allocates the new batch SLDS required for batch backout– performs the batch backout– forces the allocation of batch SLDS for jobs with no logs allocated (by specific or generic job name) – forces DBRC=Y or DBRC=N for IMS batch systems that are not generated with DBRC=FORCE (by

specific or generic job name) – using Batch Backout Manager requires no changes to any application code or JCL.


Lift non IMS locks for ESAF Indoubt threads

� ESAF indoubt notification exit routine (DFSFIDN0) identifies external subsystem indoubt units if there is an IMS failure. Non IMS locks are held as long as the indoubt UOW is resolved.

– If not used, IMS attempts to resolve the indoubt data when it can ( /ERE at a later time).

� During an emergency restart or an FDBR start, when scanning the units of work for recovery, IMS provides to the user exit routine the identities of all external subsystem units of work, the namesof the external subsystems, and the final resolutions of the data.

FIDN001I IMSID=IMS9 SSIS=DB81 Action=ABORT NID=IMS9.0000000400000000

-dis tread(*) type(indoubt)

DSNV401I ) DISPLAY THREAD REPORT FOLLOWS -

DSNV406I ) INDOUBT THREADS -

COORDINATOR STATUS RESET URID AUTHID

IMS9 INDOUBT 000226279102 BRUNEEL

V449-HAS NID= IMS9.400000000 AND ID= 0001DSN8IH0

DISPLAY INDOUBT REPORT COMPLETE

DSN9022I ) DSNVDT '-DIS THREAD' NORMAL COMPLETION

-recover indoubt (ims9) action(abort) nid(IMS9.0000000400000000)

DSNV415I ) THREAD NID=IMS9.0000000400000000 ABORT SCHEDULED

DSN9022I ) DSNVRI '-RECOVER INDOUBT' NORMAL COMPLETION

-dis thread(*) type(indoubt)

DSNV401I ) DISPLAY THREAD REPORT FOLLOWS -

DSNV420I ) NO INDOUBT THREADS FOUND

DSN9022I ) DSNVDT '-DIS THREAD' NORMAL COMPLETION


Queue Space Notification exits

� DFSQSPC0 for Local Queue: Causes a warning message to be issued when one of

following occurs:

– The number of records currently in use exceeds upper threshold percentage value of the

maximum number assignable before initiation of automatic shutdown.

– The number of records currently in use falls below the lower threshold percentage value

of the same maximum.

– Both thresholds QTU and QLU are IMS exec parameters

– DFSQSPC0 is entered for each get and free of queue space and can reject the message

segment insert

� DFSQSSP0 for Shared Queues: The following information is passed when this exit

routine runs :

– The shared queue structure is in an overflow state.

– The destination queue in a shared-queues environment is in an overflow state.


IMS Queue Control Facility V3

� QCF is a tool which can help the IMS customer manage all aspects of the IMS

Queues

– Requeue messages - after IMS cold start, after application failures, for testing, for

IMS migration, etc.

– Monitor the existing queue space usage and notify problems in time to do something

about it

– Manage the in-process IMS Queue• List and manage tasks that are flooding the queue• Query the queues to determine the kind of queue usage

by various IMS entities (input, program output, etc..).• Look at specific queue entries • View message content• Move or Copy messages to a dataset• Requeue moved or copied messages

� Non Shared Queue and Shared Queue management


Don’t process timeout messages with Transaction Expiration

� APPC/IMS timeout APPCIOT= in DFSDCxxx member or OTMA transaction expiration

EXPRTIME= parameter on TRANSACT macro

� For OTMA messages, can be set in client application or in IMS Connect with IMS

Connect Extension

� At GU time, msg is purged if timeout reached, and U0243 is produced

� Apply PM14755 / UK60112 ( IMS 11 ) to have the correct behaviour :

– The transaction and program are NOT stopped after a U0243 abend

– Msg DFS555I is produced and the input msg is not re-queued back

– A dump is produced for this abend ( normal condition )

– SLIP SET,ACTION=NODUMP,COMP=U0243,END to supress the dump


Topics

� System definition

– DRD / Repository

– ETO Support to simplify exits, not only ETO exits

– What are the Online parameters of IMS ?

� System management

– ACBLIB management

– Type 2 commands

� Optimize restart

– With Batch management

– With External Subsystems such as DB2

� Queue management

– DFSQSPC0 / DFSQSSP0

– QCF V3

– Transaction expiration

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