- 1. IMS OTMA High Availability andWorkload BalancingIMS Regional
User GroupBoston/Hartford, May 2013Prepared by: Suzie Wendler (ATS)
and Steve NathanPresented by: Steve Nathan, IMS RUG Advocate 2013
IBM CorporationThe (R)Evolution ContinuesPresented by: Steve
Nathan, IMS RUG Advocate
2. IMS Regional User Group Boston /Hartford May 2013Disclaimer
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CURRENT PRODUCT PLANS AND STRATEGY, WHICH ARESUBJECT TO CHANGE BY
IBM WITHOUT NOTICE. IBM SHALL NOT BE RESPONSIBLE FOR ANY2IMS OTMA
High Availability and Workload BalancingSUBJECT TO CHANGE BY IBM
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atwww.ibm.com/legal/copytrade.shtml 3. IMS Regional User Group
Boston /Hartford May 2013AgendaIntroduction to Sysplex, OTMA and
IMS ConnectWorkload Distribution, load balancing and
failoverconcepts DNS/WLM, VIPA, Sysplex DistributorInbound:3IMS
OTMA High Availability and Workload Balancing IMS Connect Workload
Distribution Accessing IMS as a server Transactions and Supermember
support Databases and ODBM aliasesOutbound: Calling out from IMS
Accessing external web services Addressing single points of
failureWebsphere MQ IMS Bridge 4. IMS Regional User Group Boston
/Hartford May 2013AbstractWith the ever-increasing options to
integrate IMS intothe new data processing world, care must be taken
toensure that the proper decisions are made forscalability, backup,
and failure scenarios. This sessionexplains and compares different
options includingDVIPA, Sysplex Distributor, IMS Connect
Datastore4IMS OTMA High Availability and Workload BalancingDVIPA,
Sysplex Distributor, IMS Connect Datastorerouting, the use of
aliases with ODBM to manageworkload requests for IMS resources,
considerationswhen using the new IMS callout capabilities
andWebsphere MQ IMS Bridge availability . 5. IMS Regional User
Group Boston /Hartford May 2013SysplexA group of connected system z
processors and LPARs Enables horizontal growth IMS: Shared Queues,
Data Sharing, Multiple and/or ClonedSystems, MSC routing, Provides
a single system image5IMS OTMA High Availability and Workload
BalancingInternet 6. IMS Regional User Group Boston /Hartford May
2013OTMAIMS/ESA 5.1 introduced the IMS OTMA (OpenTransaction
Manager Access) featureThis feature uses the MVS cross-coupling
facility (XCF)to send and receive data (messages and commands)6IMS
OTMA High Availability and Workload Balancingto/from IMS from MVS
applications (OTMA clients) No VTAM or TCP/IP is involved OTMA
clients do not have to be in the same LPAR as IMS They just have to
be in the same SYSPLEXThe OTMA code runs in the IMS Control Region
7. IMS Regional User Group Boston /Hartford May 2013OTMAThere is a
wide variety of OTMA clients Websphere MQ includes an IMS OTMA
client MQSeries-IMS Bridge IMS Connect is an IBM provided OTMA
client for TCP/IP DB2 Stored Procedures include an OTMA Client7IMS
OTMA High Availability and Workload Balancing DB2 Stored Procedures
include an OTMA Client DSNAIMS You can write your own OTMA client
Using the XCF Interface (VERY hard to do) Using the OTMA Callable
Interface from C or C++ programs Many vendors provide OTMA clients
8. IMS Regional User Group Boston /Hartford May 2013OTMA8IMS OTMA
High Availability and Workload Balancing 9. IMS Regional User Group
Boston /Hartford May 2013OTMAOTMA TPIPEs (Transaction Pipes) OTMA
equivalent of LTERMs Input (IOPCB) TPIPE names are specified by the
client Asynchronous output (ALTPCB) TPIPE names The destination in
the CHNG call for modifiable ALTPCBs The destination name in static
ALTPCBs9IMS OTMA High Availability and Workload Balancing The
destination name in static ALTPCBs Can be overridden by the
DFSYPRX0 exit Can be overridden by the DFSYDRU0 exit Can be
specified by DFSYDTx OTMA descriptors The name is important
Asynchronous output and synchronous callout messages are retrieved
by askingfor messages from a specific OTMA Client on a specific
TPIPE 10. IMS Regional User Group Boston /Hartford May 2013OTMAOTMA
TPIPEs (Transaction Pipes) TPIPE names must be unique only within a
client (multiple clients canuse the same TPIPE name) IMS recognizes
TPIPEs as XCFmember.TPIPEname10IMS OTMA High Availability and
Workload Balancing IMS recognizes TPIPEs as XCFmember.TPIPEname A
request for asynchronous output or synchronous callout on a
TPIPEmust come from the OTMA client (XCFmember) on which the
messagewas queued OR an OTMA Supermember must be used 11. IMS
Regional User Group Boston /Hartford May 2013OTMAOTMA TPIPEs
(Transaction Pipes) There are two types of TPIPEs: Synchronized and
Non-Synchronized Synchronized TPIPEs exchange sequence numbers and
can beresynchronized across failures11IMS OTMA High Availability
and Workload Balancing MQSeries uses Synchronized TPIPEs for CM0
messages Messages on Synchronized TPIPEs are considered recoverable
byMQSeries IMS Connect only uses and supports Non-Synchronized
TPIPEs 12. IMS Regional User Group Boston /Hartford May
2013OTMA12IMS OTMA High Availability and Workload Balancing 13. IMS
Regional User Group Boston /Hartford May 2013OTMAOTMA Synchronous
Callout OTMA supports synchronous callout from an IMS application
It is invoked with an IMS AIB call ICAL The application will issue
the call and wait for a reply13IMS OTMA High Availability and
Workload Balancing The application will issue the call and wait for
a reply First support is for IMS Connect 14. IMS Regional User
Group Boston /Hartford May 2013OTMAOTMA Synchronous Callout The
OTMA Client does a Resume TPIPE specifying that is wantssynchronous
callout messages OTMA sends the synchronous callout request to the
OTMA Client when it is14IMS OTMA High Availability and Workload
Balancing OTMA sends the synchronous callout request to the OTMA
Client when it isavailable The OTMA Client must send an ACK (or
NAK) for the request message The OTMA Client will send the reply
via a special Send-Only message The OTMA Client is responsible for
maintaining a correlation token 15. IMS Regional User Group Boston
/Hartford May 2013OTMAOTMA Synchronous Callout15IMS OTMA High
Availability and Workload Balancing 16. IMS Regional User Group
Boston /Hartford May 2013OTMAThere are several types of messages
that have to beconsidered for OTMA availability Send/Receive from
the OTMA Client Commit Mode 1 Commit Mode 0 Send Only from the OTMA
Client16IMS OTMA High Availability and Workload Balancing Send Only
from the OTMA Client Including the response to a Sync Callout
message Receive Only at the OTMA Client Sync callout request
Asynchronous output ALTPCB output IOPCB output from Send-Only
messages NAKed IOPCB output 17. IMS Regional User Group Boston
/Hartford May 2013OTMAOTMA Commit Mode Specified by the OTMA client
on each input message Determines how IOPCB output messages are sent
Similar to APPC-IMS Commit Mode17IMS OTMA High Availability and
Workload Balancing Similar to APPC-IMS Commit Mode 18. IMS Regional
User Group Boston /Hartford May 2013OTMAOTMA Commit Mode Commit
Mode 0 (CM0) - Commit-then-send Output is queued IMS sends the
output after syncpoint is complete This is like messages to a VTAM
terminal18IMS OTMA High Availability and Workload Balancing OTMA
always requires an ACK to dequeue the output message ALTPCB output
messages and Sync Callout messages are alwaysCommit Mode 0
WebSphere MQ calls these asynchronous messages The output is
asynchronous from syncpoint completion 19. IMS Regional User Group
Boston /Hartford May 2013OTMAOTMA Commit Mode Commit Mode 1 (CM1) -
Send-then-commit IMS sends the IOPCB output and may wait for an ACK
before syncpointis complete Synch level 0 (None) no ACK continue
syncpoint19IMS OTMA High Availability and Workload Balancing Synch
level 1 (Confirm) wait for ACK Synch level 2 (Synchpoint) wait for
ACK + RRS Increases region occupancy WebSphere MQ calls these
synchronous messages The output message is synchronous with
syncpoint completion 20. IMS Regional User Group Boston /Hartford
May 2013OTMAOTMA Commit Mode Commit Mode 1 - Send-then-commit
Output messages are not queued If the message can not be sent to
the client or is NAKed by the client20IMS OTMA High Availability
and Workload Balancing If the message can not be sent to the client
or is NAKed by the client(SL1) the transaction abends with U0119
and backs out CM1 is required for Conversational and Fast Path EMH
messages 21. IMS Regional User Group Boston /Hartford May
2013OTMAOTMA Commit Mode Commit Mode 1 - Send-then-commit CM1 input
messages are ALWAYS treated as non-recoverable They will be
discarded during IMS restart if they have not processed yet21IMS
OTMA High Availability and Workload Balancing CM1 messages can not
be sent on Synchronized TPIPEs CM1 messages are always treated as
RESPONSE mode This may result in DFS2082 reply messages A CM1
transaction that message switches can produce CM0 output This can
be very complicated and result in un-retrieved output 22. IMS
Regional User Group Boston /Hartford May 2013IMS ConnectIMS Connect
is an IBM provided IMS OTMA client IMS Connect comes with IMS it is
not an additional productIMS Connect is also a TCP/IP server22IMS
OTMA High Availability and Workload Balancing The user TCP/IP
applications are the IMS Connect Clients 23. IMS Regional User
Group Boston /Hartford May 2013IMS ConnectIMS Connect accepts input
from and sends outputmessages to the IMS Connect Client IMS TM
Resource Adapter IBM supplied JEE Client MFS Web Services IBM
supplied JEE Client23IMS OTMA High Availability and Workload
Balancing IBM supplied JEE Client IMS SOAP Gateway IBM supplied
SOAP interface Any TCP/IP application Could be written using the
IMS Connect APIs for Java and C/C++ IMS Universal Type-4 Drivers or
DRDA Client For sending remote database calls to IMS Open Database
24. IMS Regional User Group Boston /Hartford May 2013IMS
Connect24IMS OTMA High Availability and Workload Balancing 25. IMS
Regional User Group Boston /Hartford May 2013IMS ConnectIMS Open
Database25IMS OTMA High Availability and Workload Balancing 26. IMS
Regional User Group Boston /Hartford May 2013IMS ConnectConfiguring
for availability is done by having multiplecopies of IMS and IMS
Connect in an IMSPLEX acrossmultiple z/OS LPARSTCP/IP availability
is provided in front of the IMSConnects26IMS OTMA High Availability
and Workload BalancingConnectsMethods are provided for routing
messages to andreceiving synchronous callout and asynchronous
outputfrom available IMS regions 27. IMS Regional User Group Boston
/Hartford May 2013IMS ConnectThe first place to configure for IMS
Connect availabilityis in the TCP/IP network that is sending and
receivingthe messagesThere are three main services available for
TCP/IP load27IMS OTMA High Availability and Workload
Balancingbalancing and failover Static VIPA Dynamic VIPA Sysplex
Distributor 28. IMS Regional User Group Boston /Hartford May
2013Workload Distribution and Load Balancing ConceptsDispatcher
support - IP Spraying Intercepts connection requests Attempts to
balance traffic by choosing and then forwarding the request to
aspecific server, e.g., a specific instance of IMS Connect, in the
sysplex.Establishes session with WLM if servers are z/OS Balances
workload based on workload goalsLoad Balancing - e.g., WebSphere
Edge Components28IMS OTMA High Availability and Workload Balancing
Balances workload based on workload goals Never selects an
unavailable serverProvides scalability and failover Detects new
instances of a server as they are added Detects server failure and
prevents routing new connection requests to themUsed for "short
duration" applications like web traffic Inbound data goes through
the router Outbound data goes directly to the client 29. IMS
Regional User Group Boston /Hartford May 2013Workload Distribution
and Load Balancing ConceptsLoad Balancing - e.g., WebSphere Edge
Components29IMS OTMA High Availability and Workload Balancing 30.
IMS Regional User Group Boston /Hartford May 2013FailoverStatic
Virtual IP Addressing (VIPA) First VIPA implementation Eliminates
an applications dependence on a particular network interface
(IPaddress) Non-disruptive rerouting of traffic in the event of
failure A defined VIPA does not relate to any physical network
attachmentStatic VIPA30IMS OTMA High Availability and Workload
Balancing Multiple network interfaces on a single TCP/IP stack 31.
IMS Regional User Group Boston /Hartford May 2013FailoverAutomatic
VIPA Takeover Support for other TCP/IP stacks to be backup VIPA
address Allows an active stack to assume the load of a failing
stack Stacks share information using z/OS XCF messagingDynamic
VIPA31IMS OTMA High Availability and Workload Balancing 32. IMS
Regional User Group Boston /Hartford May 2013Sysplex
DistributorSysplex function - Single IP address for a cluster of
Hosts Sysplex-wide VIPA Workoad balancing across multiple z/OS
servers Performs a Load Balancer type function on the System z
environment High availability Enhanced Dynamic VIPA and Automatic
Takeover Allows movement of VIPAs without disrupting existing
connections32IMS OTMA High Availability and Workload Balancing 33.
IMS Regional User Group Boston /Hartford May 2013Sysplex
Distributorz/OS Communications Server includes Server-Specific WLM
for Sysplex Distributor Connections are distributed using a
round-robin distribution Or, based on a target servers (IMS
Connects ports) workload capacity Rather than the target systems
(z/OS TCP/IP stack) capacity Will be implemented for ICON in IMS
1333IMS OTMA High Availability and Workload Balancing Balancing can
also be done across a group of servers (multiple IMSConnect
instances) sharing a port Sysplex autonomics health monitor for
target stacks Provides a mechanism to monitor a target servers (IMS
Connects ports)connection setup responsiveness Approximately 1
minute intervals When connection responsiveness diminishes, new
connection requestsare diverted to alternate instances of the
server 34. IMS Regional User Group Boston /Hartford May 2013IMS
ConnectIn a Sysplex Distributor environment34IMS OTMA High
Availability and Workload Balancing 35. IMS Regional User Group
Boston /Hartford May 2013Routing Examples Important NoteAlthough
the Sysplex Distributor is an efficientmechanism for workload
balancing Balancing only occurs when a new connection is being
established If an IMS Connect region fails New connection requests
are automatically routed to the remaining active IMSConnect regions
and workload balancing occurs among the active regions When the
failed IMS Connect is restarted35IMS OTMA High Availability and
Workload Balancing When the failed IMS Connect is restarted
Connections that are already active with other IMS Connect regions
are NOTre-balanced Only NEW connections are routed to the restarted
region Implication: Many of the connections with IMS Connect are
persistent The environment after an IMS Connect has failed and been
restarted, might beunbalanced until enough new connections have
been requested. 36. IMS Regional User Group Boston /Hartford May
2013Port SharingA method to distribute workload for IP
applicationswithin a z/OS LPAR Multiple instances of an application
can listen on the same PORTnumber Allows the workload to be
distributed among the server applicationslistening on the same port
Simplifies the request for the remote client that does not know
there36IMS OTMA High Availability and Workload Balancing Simplifies
the request for the remote client that does not know theremight be
multiple server application instances that can accept themessage
Works with the Sysplex Distributor but does not require it Can be
implemented using round-robin distribution or with theworkload
manager 37. IMS Regional User Group Boston /Hartford May 2013IMS
ConnectIMS Connect can listen on multiple TCP/IP Ports This is
important for availability and performance Each Port is a TCB in
IMS Connect Multiple Ports allow more multi-tasking with IMS
Connect Each Socket connection is a sub-task with the Port TCB37IMS
OTMA High Availability and Workload Balancing Each Socket
connection is a sub-task with the Port TCB One socket with a very
large message or a network problem could tie upthe entire Port It
is up to the customer to have different IMS Connect Clients
usedifferent Ports 38. IMS Regional User Group Boston /Hartford May
2013IMS ConnectPORTS Provide the mechanism to access different IMS
resources Specified in the HWSCFGxx configuration file PORTID -
defines the PORT numbers for access to IMS TMapplications and
commands PORT - defines the PORT numbers, distinct from those
defined inPORTID Also for access to IMS TM applications and
commands but you to specify38IMS OTMA High Availability and
Workload Balancing Also for access to IMS TM applications and
commands but you to specifyan override of the TCP/IP Keepalive
specification and to specify a PORTedit exit SSLPORT defines the
Secure Socket Layer port This should not be used use TCP/IP AT-TLS
DRDAPORT (IMS V11) Defines the PORT numbers, distinct from those
defined in the PORT orPORTID statements, used specifically for
access to IMS DB. 39. IMS Regional User Group Boston /Hartford May
2013IMS ConnectConnections to OTMA One IMS Connect can connect to
multiple IMS Control Regions inmultiple XCF groups One IMS Connect
can have multiple connections to the same IMScopy39IMS OTMA High
Availability and Workload Balancing Each connection is a separate
OTMA client Each OTMA client is a separate TCB in IMS Each
connection is called a datastore in IMS Connect Each connection can
have multiple TPIPEs One for each Port for CM1 messages One for
each IMS Connect Client for CM0 messages 40. IMS Regional User
Group Boston /Hartford May 2013IMS Connect40IMS OTMA High
Availability and Workload Balancing 41. IMS Regional User Group
Boston /Hartford May 2013IMS ConnectDATASTORE Specified by
DATASTORE control card in HWSCFGxx Identifies a connection to an
IMS There can be multiple DATASTORE control cards Translates a
logical datastore name passed by the ICON client into theIMS XCF
member name and therefore IMS Control Region41IMS OTMA High
Availability and Workload Balancing This allows for reconfiguring
IMS applications without changing IMS ConnectClient code ID= The
logical datastore name This is what is passed by the IMS Connect
client to identify the IMS copy toreceive the message It can be
set/overridden by the IMS Connect User Message Exit 42. IMS
Regional User Group Boston /Hartford May 2013IMS ConnectDATASTORE
Specified by DATASTORE control card in HWSCFGxx GROUP= Name of the
XCF group to join for this connection TMEMBER= XCF member name of
the IMS to connect to for thisdatastore There can be multiple
DATASTORE cards Each DATASTORE is an OTMA client (TMEMBER)42IMS
OTMA High Availability and Workload Balancing Each DATASTORE is an
OTMA client (TMEMBER) MEMBER= XCF member name of ICON for this
connection This is the OTMA Client name (TMEMBER) 43. IMS Regional
User Group Boston /Hartford May 2013IMS Connect Workload Balancing
and FailoverOnce a message destination is resolved to a particular
z/OS hostand IMS Connect system IMS Connect can access multiple IMS
Systems (datastores) Message exits can reroute a message to a
different target IMS The Datastore table provides information as to
which systems are active43IMS OTMA High Availability and Workload
Balancing 44. IMS Regional User Group Boston /Hartford May
2013Routing ExamplesTwo tables available to IMS Connect User
Message exits Exit Interface Block (HWSXIB) Points to the datastore
table Allows user data to be stored Datastore Table (HWSXIBDS)
(datastore = connection to an IMSsystem)44IMS OTMA High
Availability and Workload Balancing Contains datastore ids, status
(active, inactive, degraded) and optionaluser dataUser
Initialization Exit Routine (HWSUINIT) Driven during initialization
and termination Load user table(s) and obtain any needed storage
Add user data to Exit Interface and DATASTORE tables e.g., define
alternate IMS systems 45. IMS Regional User Group Boston /Hartford
May 2013Routing ExamplesExit Interface Block IMS Connect
information Pointer to the Datastore tableHWSXIB DSECT Exit
Interface Block
00200000***********************************************************************
00210000* XIB Header *
00220000***********************************************************************
00230000XIB_HEADER DS 0D 00240000XIB_EYE DS CL4XIB EYECATCHER
0025000045IMS OTMA High Availability and Workload BalancingXIB_EYE
DS CL4XIB EYECATCHER 00250000XIB_DATASTORES DS A DataStore list
address 00260000XIB_UFLD_CNT DS F User field count
00270000XIB_XIBDS_LEN DS H Length of XIBDS Entry @PK70960
00280000XIB_ARCHLVL DS X Architecture Level @PK70960
00280100XIB_ARCH1 EQU X01 Arch Level 1 @PK70960 00280200XIB_ARCH2
EQU X02 Arch Level 2 @PM05993 00280250XIB_ARCHMAX EQU XIB_ARCH2
Highest Arch Level @PM05993 00280300* Set Arch Level to 2 @PM05993
00280310DS X Reserved for IMS Connect @PK70960 00280400XIB_VERSION
DS F Version X0A0100=V10.1.0 @PM05993 00280450DS F Aligned with V11
@PM17288 00280470DS 3F Reserved for IMS Connect @PM05993 00280500*
@PM05993 00280600XIB_HDR_LEN EQU *-HWSXIB XIB header fixed length
00290000 46. IMS Regional User Group Boston /Hartford May
2013Routing ExamplesDatastore Table List of datastores and their
status Can be used to route messages to available, un-degraded IMS
copiesHWSXIBDS DSECT Exit Interface Block Data Store
entryXIBDS_NAME DS CL8 Data store nameXIBDS_STATUS DS X Data store
status46IMS OTMA High Availability and Workload
BalancingXIBDS_STATUS DS X Data store statusXIBDS_INACTIVE EQU X00
Data store not active in ICON* OPENDS command is
requiredXIBDS_ACTIVE EQU X01 Data store active in ICON* And IMS is
active in XCF groupXIBDS_DISC EQU X02 Data store disconnected* No
OPENDS command is requiredXIBDS_FLAG DS X Data store entry
flagsXIBDS_LAST_ENTRY EQU X80 Last entry in listDS XL2
ReservedXIBDS_USER DS XL4 User field 47. IMS Regional User Group
Boston /Hartford May 2013Routing ExamplesDatastore Table Contains
degraded status and last heartbeat timestampXIBDS_USER DS XL4 User
field* OTMA Status Section FollowsXIBDS_ST_STATUS DS H Overall
Status Code 3, 2, or 1* 3 - Available for work* 2 - Warning, partly
degraded* 1 - Severe, no work possible* 0 - N/A no status
availableXIBDS_ST_SVRSTT DS 0XL4 Unavailable resource
infoXIBDS_ST_SVRFLG1 DS X Group 1 unavail resourcesXIBDS_ST_SVRFLG2
DS X Group 2 unavail resourcesXIBDS_ST_SVRFLG3 DS X Group 3 unavail
resources47IMS OTMA High Availability and Workload
BalancingXIBDS_ST_SVRFLG3 DS X Group 3 unavail
resourcesXIBDS_ST_SVRFLG4 DS X Group 4 unavail
resourcesXIBDS_ST_S4FLOOD EQU X01 Member reaches 100%
floodXIBDS_ST_WRNSTT DS 0XL4 Degraded resource infoXIBDS_ST_WRNFLG1
DS X Group 1 degraded resourcesXIBDS_ST_W1FLOOD EQU X80 Global
flood warningXIBDS_ST_W1MTP EQU X40 Global tpipe
warningXIBDS_ST_WRNFLG2 DS X Group 2 degraded
resourcesXIBDS_ST_WRNFLG3 DS X Group 3 degraded
resourcesXIBDS_ST_WRNFLG4 DS X Group 4 degraded
resourcesXIBDS_ST_W5MTP EQU X08 Member TPIPE reached
100%XIBDS_ST_W4MTP EQU X04 Member TPIPE reached 80%XIBDS_ST_AWE EQU
X02 Msg AWE reaches 80% floodXIBDS_ST_W4FLOOD EQU X01 Member 80%+
floodXIBDS_ST_UTC DS CL12 UTC time for this statusXIBDS_ST_LEN EQU
*-XIBDS_ST_STATUS Length of OTMA Status 48. IMS Regional User Group
Boston /Hartford May 2013Routing ExamplesDatastore Routing IMS
Connect provides the interface IMS Connect sample User Message
Exits do not take advantage ofthe capability They can be modified
to do so48IMS OTMA High Availability and Workload Balancing
Plug-ins such as IMS Connect Extensions (CEX) provide
extensiverouting support 49. IMS Regional User Group Boston
/Hartford May 2013IMS Connect49IMS OTMA High Availability and
Workload Balancing 50. IMS Regional User Group Boston /Hartford May
2013IMS ConnectThe use of mechanisms such as IP spraying,
workloadbalancing and sysplex distribution Allow a connection
request to be routed to any of the available IMSConnect instances
Different versions of IMS Connect and IMS can coexist Mixed
versions of IMS Connect and IMS are limited to the functionality of
thelower release level50IMS OTMA High Availability and Workload
Balancinglower release levelLPAR3LPAR2IMS Connect 1 (V11)IMS
Connect 2 (V11)IMS A (V11)IMS B (V11)IMS C (V12)IMS Connect 3
(V12)LPAR1TCP/IPTCP/IPTCP/IP 51. IMS Regional User Group Boston
/Hartford May 2013ConsiderationsConnection failures What happens to
the outputmessages? Depends on Commit Mode Send-then-Commit (CM1)
Sync_level=none messages are discarded 119 abend only for IMS
Connect failure51IMS OTMA High Availability and Workload Balancing
Sync_level=confirm messages result in 119 abends Commit-then-send
(CM0) Always Sync_level=confirm Undelivered messages stay queued in
IMS Retrieved with a Resume TPIPE request from remote client The
OTMA Client can specify that the message be routed to a different
TPIPE The OTMA Client can specify that the message be purged
instead of queued 52. IMS Regional User Group Boston /Hartford May
2013ConsiderationsLoad Balancing --- vs --- CM0 messages on the IMS
queue Includes undelivered IOPCB messages along with all
unsolicitedALTPCB messages Resume TPIPE requests to retrieve the
output message Must be routed to IMS Connect that directly or
indirectly triggered theoutput52IMS OTMA High Availability and
Workload Balancingoutput On a new connection, the load balancing
function may route the request toa different IMS Connect instance
In a Shared Queues environment The IMS system that processes an
ALTPCB message must also deliver it IMS Connect needs to route the
Resume TPIPE request to thatspecific IMS instance 53. IMS Regional
User Group Boston /Hartford May 2013ConsiderationsResume TPIPE with
a SYSPLEX Distributor If you have a SYSPLEX Distributor in front of
multiple OTMA Clientsyou may have problems using Resume TPIPE to
retrieve yourasynchronous output The inputting transaction may be
routed to one OTMA Client and the53IMS OTMA High Availability and
Workload Balancing The inputting transaction may be routed to one
OTMA Client and theResume TPIPE routed to a different OTMA Client
This can be fixed by the Supermember concept This allows multiple
clients to pool their asynchronous output 54. IMS Regional User
Group Boston /Hartford May
2013ConsiderationsIMSICON1OTMAICON1.TPIPE1IMSSend-OnlySend-OnlySend-Only
is sent toICON1 and output isqueued to ICON1.TPIPE154IMS OTMA High
Availability and Workload
BalancingIMSConnectClientSYSPLEXDISTRIBUTORICON2ICON1.TPIPE1ICON2.TPIPE1Resume
TPIPEResume TPIPEResume TPIPE is sent toICON2 and output is
notfound on ICON2.TPIPE1 55. IMS Regional User Group Boston
/Hartford May 2013Supermember SupportSolution Supermember Support
(OPTIONAL) A group member name given to a set of IMS Connect
instances on whichto queue their asynchronous output Any IMS
Connect using the same Supermember can retrieve theasynchronous
output55IMS OTMA High Availability and Workload
Balancingasynchronous output For Shared Queues, no affinity to an
IMS system Any IMS can deliver the message 56. IMS Regional User
Group Boston /Hartford May 2013Supermember
SupportIMSConnectICON1SMEMBER=SME1OTMAICON1.TPIPE1IMSSend-OnlySend-OnlySend-Only
is sent toICON1 and output isqueued to SME1.TPIPE156IMS OTMA High
Availability and Workload
BalancingConnectClientSYSPLEXDIRECTORICON2SMEMBER=SME1ICON1.TPIPE1ICON2.TPIPE1SME1.TPIPE1Resume
TPIPEResume TPIPEResume TPIPE is sent toICON2 and output isfound on
SME1.TPIPE1 57. IMS Regional User Group Boston /Hartford May
2013Supermember
SupportIMSConnectSend-OnlySYSPLEXDISTRIBUTORICON1SMEMBER=SME1OTMAIMSSend-OnlyCFIMS
SQ12357IMS OTMA High Availability and Workload
BalancingConnectClient Resume
TPIPEResumeTPIPEICON2SMEMBER=SME1OTMAIMSIMS
SQICON1.TPIPE1ICON2.TPIPE1SME1.TPIPE1Super member alsoworks in an
IMSShared Queuesenvironment3 4 58. IMS Regional User Group Boston
/Hartford May 2013So For Transaction AccessThrough Sysplex
distribution and Supermember support58IMS OTMA High Availability
and Workload Balancing 59. IMS Regional User Group Boston /Hartford
May 2013Multiple IMS Systems and Shared Queues SupportIf the IMS
systems are cloned IMS Connect routing mechanisms can send messages
to differentIMSs for processingOr, with the use of IMS Shared
Queues CM0 (Commit-then-Send) messages can process in any
back-end59IMS OTMA High Availability and Workload Balancing CM0
(Commit-then-Send) messages can process in any back-end CM1
(Send-then-Commit) synchronous processing in a back-endsystem Use
zOS RRS (Resource Recovery Services) Until IMS 12 60. IMS Regional
User Group Boston /Hartford May 2013Multiple IMS Systems and Shared
Queues SupportShared Queues IMS 11 (without RRS) No Synchronous
processing in the back-end, UNLESS DFSMSCE0 specifies MSCEFL2 =
MSCE2FAF Requests CM1 Sync (NONE|CONFIRM) to process in the IMS B-E
IMS maintains connection to the client on the front-end system
while processing themessage as a non-APPC/OTMA message within the
IMSplex environment60IMS OTMA High Availability and Workload
Balancingmessage as a non-APPC/OTMA message within the IMSplex
environment Response message is converted back to APPC/OTMA
synchronous mode, and theresponse is queued to the client. MSC must
be defined (although it is not used) IMS 12 New DFSDCxxx option to
request synchronous Sync (NONE | CONFIRM)requests be processed on a
back-end system Using XCF services (not RRS) 61. IMS Regional User
Group Boston /Hartford May 2013How About Database Access?With IMS
11, IMS Connect along with the Open Database Manager(ODBM) provide
IMS database access IMS Connect supports load balancing and Sysplex
distribution for thisenvironment The DRDA port number can also be
shared across multiple instances61IMS OTMA High Availability and
Workload Balancing 62. IMS Regional User Group Boston /Hartford May
2013How About Database Access?IMS Connect does not define the ODBM
address spacesto be connected to It only defines the Ports to
listen on and the IMSPLEX to
joinHWS=(ID=HWS1,XIBAREA=100,RACF=N)TCPIP=(HOSTNAME=TCPIP,PORTID=(9999,9998,LOCAL),EXIT=(HWSSMPL1,HWSCSLO1,HWSSOAP1))DATASTORE=(ID=IMS1,GROUP=XCFGRP1,MEMBER=HWS1,62IMS
OTMA High Availability and Workload
BalancingDATASTORE=(ID=IMS1,GROUP=XCFGRP1,MEMBER=HWS1,TMEMBER=IMS1,DRU=HWSYDRU0,APPL=APPLID1,RRNAME=RTPIPE)IMSPLEX=(MEMBER=ICONCC1,TMEMBER=PLEX1)ADAPTER=(XML=Y)ODACCESS=(ODBMAUTOCONN=Y,ODBMTMOT=6000,DRDAPORT=(ID=1111,KEEPAV=5,PORTTMOT=50),IMSPLEX=(MEMBER=ICONOD2,TMEMBER=PLEX2))
63. IMS Regional User Group Boston /Hartford May 2013How About
Database Access?ODACCESS Statement in IMS Connect Only DRDAPORT= is
needed to define IMS Connect as a DRDAserver There can be multiple
occurrences of DRDAPORT ODBMAUTOCONN=Y|N Y IMS Connect registers
with all current and future ODBMs that enterthe IMSplex N IMS
Connect does not automatically register with any ODBMs63IMS OTMA
High Availability and Workload Balancing N IMS Connect does not
automatically register with any ODBMs Defaults to N if not
specified ODBMTMOT= Defines the amount of time that IMS Connect
waits for both ODBM and theDRDA Client IMSPLEX=(MEMBER=,TMEMBER=)
Defines the IMSPLEX to connect to If not specified the top level
IMSPLEX statement will be used 64. IMS Regional User Group Boston
/Hartford May 2013How About Database Access?IMS Copies and their
aliases are defined to ODBM in theCSLDCxxx member in the IMS
PROCLIB/*********************************************************************//*
Define DATASTORE properties for ODBM01
*//**********************************************************************/ODBM(NAME=ODBM01,
/* Define parms for ODBM01 */DATASTORE(NAME=IMS1, /* IMSID on LPAR
A */ALIAS(NAME=IO1A,NAME=IO1B), /* Names for APPL sets 1 &
2*/FPBUF=0,FPBOF=0,CNBA=0 /* No FastPath on this IMS */64IMS OTMA
High Availability and Workload BalancingFPBUF=0,FPBOF=0,CNBA=0 /*
No FastPath on this IMS */)DATASTORE(NAME=IMS2, /* IMSID on LPAR A
*/ALIAS(NAME=IO2A,NAME=IO2B), /* Names for DEDB apps
*/FPBUF=50,FPBOF=50,CNBA=500, /* FastPath on this IMS */MAXTHRDS=5
/* Throttle down threads */)) 65. IMS Regional User Group Boston
/Hartford May 2013How About Database Access?IMS Copies and their
aliases are defined to ODBM in theCSLDCxxx member in the IMS
PROCLIB/**********************************************************************//*
Define DATASTORE properties for ODBM02
*//**********************************************************************/ODBM(NAME=ODBM02,
/* Define parms for ODBM02 */DATASTORE(NAME=IMS3, /* IMSID on LPAR
B */ALIAS(NAME=IO3A,NAME=IMS3) /* Names for APPL sets 3 & 4
*/65IMS OTMA High Availability and Workload
BalancingALIAS(NAME=IO3A,NAME=IMS3) /* Names for APPL sets 3 &
4 */) /* Take global for the rest */) 66. IMS Regional User Group
Boston /Hartford May 2013How About Database Access?ODBM
automaticallyconnects during initializationto IMS systems specified
inCSLDCxxxODBM attempts auto-(re)connect with an IMS afterreceiving
the SCI notify
thatIMS2ODBAIMS1SCIODBMIMSPLEX(NAME=PLEX1)PLEX1PLEX166IMS OTMA High
Availability and Workload Balancingreceiving the SCI notify
thatthis IMS has (re)joined theIMSplex e.g. IMS2 will
auto-reconnectODBM can connect to an IMSthat is not in an IMSplex
Auto-reconnect not available e.g. IMS4 will not
auto-reconnectIMS4LPAR 1PLEX1 PLEX1 67. IMS Regional User Group
Boston /Hartford May 2013How About Database Access?When ODBM
connects to IMS Connect it will pass all of itsAlias names to IMS
Connect Multiple ODBMs can use the same Alias name(s)When a DRDA
client sends a request to IMS Connect itwill pass a real alias name
or a blank alias name67IMS OTMA High Availability and Workload
BalancingIf the alias name is blank IMS Connect will round-robin
therequest among all of the ODBMsIf the alias name is real IMS
Connect will round-robin therequest among all the ODBMs containing
that Alias nameOnce the request gets to ODBM, ODBM will
round-robinthe request among all of the IMS copies with that alias
68. IMS Regional User Group Boston /Hartford May 2013Database
AccessCalling programs can use an alias name to access IMSdata
stores without needing to know the actual IMSID ofthe IMS data
storeODBAODBMB1IMS1TM/DBIMSConnect
ALPARAODBM(NAME=ODBMB1DATASTORE(NAME=IMS1,ALIAS(NAME=IM1A,
IO1A))DATASTORE(NAME=IMS2,ALIAS(NAME=IM1A, IO2A)) )ALIAS IO1A only
routes to IMS1IMSPLEX1DB68IMS OTMA High Availability and Workload
BalancingIMS2TM/DBODBAODBMB1ALIAS IO2A only routes to
IMS2ODBMB2DRAALIAS IO3A only routes to IMS3) LPARBIMSConnect
BTCP/IPACCESSDB usingALIAS IM1AAnd
usingIMSConnectHostnameport*Alias IM1A isrouted to
ODBMB1DBDBIMS4DBCTL DBIMS4 has no alias, applications can use the
DATASTORE name
IMS4IMS3DBCTLODBM(NAME=ODBMB2DATASTORE(NAME=IMS3,ALIAS(NAME= IO3A,
IMS3))DATASTORE(NAME=IMS4) ) 69. IMS Regional User Group Boston
/Hartford May 2013Database AccessWithout an alias, IMS Connect
routes incoming connections inround-robin fashion among all the
instances of ODBM within theIMSplex69IMS OTMA High Availability and
Workload Balancing 70. IMS Regional User Group Boston /Hartford May
2013Database AccessIMS Connect has an internal table Keeps track of
ODBMS and the IMS datastores and aliasesIMS Connect DB Routing Exit
routine (HWSROUT0) Can determine or change the destination of a
database accessrequest Select an ODBM by its name70IMS OTMA High
Availability and Workload Balancing Select an ODBM by its name
Allow IMS Connect to select an ODBM instance By alias name If only
one ODBM has specified the alias, the request is routed to that
ODBM If the alias is associated with multiple ODBMs then IMS
Connect uses a round-robintechnique to route the request across
those resources. If the alias is blanks then IMS Connect
round-robins the request across all theODBM resources in the
IMSplex. Override the alias provided in the incoming request 71.
IMS Regional User Group Boston /Hartford May 2013And For Outbound
RequestsIMS applications as clients to remote web services IMS DL/I
call ICAL sends messages through IMS Connect to: EJB/MDB on a JEE
server, e.g., WebSphere Application Service Soap clients through
IMS ES Soap Gateway RYO clients Remote systems need to issue Resume
TPIPE to retrieve messages71IMS OTMA High Availability and Workload
Balancing IMS TM RA for JEE, IMS ES Soap Gateway, RYO 72. IMS
Regional User Group Boston /Hartford May 2013And For Outbound
RequestsMultiple applications/servers may be configured to pullIMS
callout messages on the same destination foravailability If one
server fails, the other server can continue to pull calloutmessages
from IMS Servers are pre-conditioned to issue Resume TPIPE requests
Failover support for OTMA allows queuing of Resume TPIPEs72IMS OTMA
High Availability and Workload Balancing Failover support for OTMA
allows queuing of Resume TPIPEs IMS 10 APAR PK80758/ PTF UK50686
IMS V11 APAR PK91374/ PTF UK52368 First Resume TPIPE is active
until satisfied and subsequent ResumeTPIPEs are queued IMS Command:
/DISPLAY TMEMBER TPIPE SYNC Shows the number of queued Resume TPIPE
on Hold Queue requests(RTQ) and the active Resume TPIPE status 73.
IMS Regional User Group Boston /Hartford May 2013And For Outbound
RequestsStep 1 - Redundancy73IMS OTMA High Availability and
Workload Balancing 74. IMS Regional User Group Boston /Hartford May
2013And For Outbound RequestsTarget Redundancy with Failover74IMS
OTMA High Availability and Workload Balancing 75. IMS Regional User
Group Boston /Hartford May 2013WebSphere MQWebSphere MQ contains an
OTMA client WebSphere MQ IMS Bridge Code in the WebSphere MQ Queue
Manager For specially defined queues it will MQGET the messages
from thequeue and send them to IMS using the OTMA interface The IMS
bridge also gets output messages from IMS via the OTMA75IMS OTMA
High Availability and Workload Balancing IOPCB output is MQPUT to
the Reply-to Queue and Reply-to QueueManager in the original MQ
input message ALTPCB output can also be routed to the IMS Bridge
Sync Callout is currently not supported One WebSphere MQ Queue
Manager can connect to multiple IMSControl Regions There can only
be one connection per IMS Control Region All IMS Control Regions
must be in the same XCF group 76. IMS Regional User Group Boston
/Hartford May 2013WebSphere MQ76IMS OTMA High Availability and
Workload Balancing 77. IMS Regional User Group Boston /Hartford May
2013WebSphere MQ77IMS OTMA High Availability and Workload Balancing
78. IMS Regional User Group Boston /Hartford May 2013WebSphere
MQThere would be one definition for a Shared IMS BridgeQueue DEFINE
QLOCAL(SBQ1) STGCLASS(IMS1) But each Queue Manager would have its
own non-shared definition forSTGCLASS IMSX78IMS OTMA High
Availability and Workload BalancingSTGCLASS IMSX MQ1: DEF
STGCLASS(IMSX) XCFNAME(IMS1) QSGDISP(QMGR) MQ2: DEF STGCLASS(IMSX)
XCFNAME(IMS2) QSGDISP(QMGR) The message will be put on the
WebSphere MQ shared queue by anyreceiving Queue Manager The message
can be retrieved from the MQ shared queue and sent toIMS by any
Queue Manager which currently has a connection to IMS 79. IMS
Regional User Group Boston /Hartford May 2013SummaryIMS Connect as
a standard TCP/IP server application Fully participates in IP
spraying and load balancing techniques VIPA, Dynamic VIPA, Sysplex
Distributor . Provides mechanisms to route requests to any IMS in
the sysplex Transaction resources Support for unsolicited messages
with the supermember capability Exit interfaces to route/reroute
messages Across LPAR boundaries79IMS OTMA High Availability and
Workload Balancing Across LPAR boundaries Database resources
Provides round-robin routing Supports aliasing Provides exit
interfaces to impact routing decisionsWebSphere MQ WebSphere MQ
Shared Queues and IMS Shared Queues can providea highly available
environment
