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IBM GDPS Active-Active and IMS Replication
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IBM GDPS Active-Active and IMS Replication
Greg Vance
IMS Development, STSM
Availability. References in this presentation to IBM products, programs, or services do not imply that they will be available in all
countries in which IBM operates.
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or otherwise related to, this presentation or any other materials. Nothing contained in this presentation is intended to, nor shall have the
effect of, creating any warranties or representations from IBM or its suppliers or licensors, or altering the terms and conditions of the
applicable license agreement governing the use of IBM software.
All customer examples described are presented as illustrations of how those customers have used IBM products and the results they may
have achieved. Actual environmental costs and performance characteristics may vary by customer. Nothing contained in these
materials is intended to, nor shall have the effect of, stating or implying that any activities undertaken by you will result in any specific
sales, revenue growth or other results.
2
© Copyright IBM Corporation 2013. All rights reserved.
– U.S. Government Users Restricted Rights - Use, duplication or disclosure restricted by GSA ADP Schedule Contract
with IBM Corp.
IBM, the IBM logo, ibm.com, IMS, DB2, CICS and WebSphere MQ are trademarks or registered trademarks of International Business
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Agenda
• Level set
• Concepts
• Sample Scenarios
3
• IMS Replication
• Summary
Suite of GDPS service products to meet various business requirements for availability and disaster recovery
Continuous Availability of Data
within a Data Center
GDPS/PPRC HM
RPO=0
[RTO secs]for disk only
Disaster Recovery Extended Distance
GDPS/GM & GDPS/XRC
RPO secs, RTO<1h
CA Regionally and Disaster Recovery Extended Distance
GDPS/MGM & GDPS/MzGM
RPO=0,RTO mins/<1h
& RPO secs, RTO<1h
Continuous Availability with
DR within Metropolitan Region
GDPS/PPRC
RPO=0RTO mins / RTO<1h
(<20km) (>20km)
4
Single Data Center
Applications remain active
Continuous access to data in
the event of a storage outage
Two Data Centers
Rapid Systems D/R w/ “seconds”
of data loss
Disaster Recoveryfor out of region
interruptions
Three Data Centers
High availability for site disasters
Disaster recovery for regional disasters
RPO – recovery point objective RTO – recovery time objective
Two Data Centers
Systems remain active
Multi-site workloads can withstand site
and/or storage failures
How Much Interruption can your Business Tolerate?
Ensuring Business Continuity:
• Disaster Recovery – Restore business after an unplanned outage
• High-Availability – Meet Service Availability objectives e.g., 99.9% availability or
8.8 hours of down-time a year
• Continuous Availability – No downtime (planned or not)
Standby
Active/Active
5
Global Enterprises that operate across time-zones no longer have any ‘off-hours’ window.Continuous Availability is required.
What is the cost of 1 hour of downtime during core business hours?
Active/Active
• Shift focus from failover model to near-continuous availability model (RTO near zero)
• Access data from any site (unlimited distance between sites)
• Multi-sysplex, multi-platform solution – “Recover my business rather than my platform technology”
• Ensure successful recovery via automated processes(similar to GDPS technology today)
– Can be handled by less-skilled operators
Evolving customer requirements
6
– Can be handled by less-skilled operators
• Provide workload distribution between sites (route around failed sites, dynamically select sites based on ability of site to handle additional workload)
• Provide application level granularity– Some workloads may require immediate access from every site, other
workloads may only need to update other sites every 24 hours (less critical data)
– Current solutions employ an all-or-nothing approach (complete disk mirroring, requiring extra network capacity)
From High Availability to Continuous Availability
• GDPS/Active-Active is for mission critical workloads that
GDPS/PPRC GDPS/XRC or GDPS/GM GDPS/Active-Active
Failover Model Failover Model Near CA model
Recovery Time ≈ 2 min Recovery Time < 1 hour Recovery time < 1 minute
Distance < 20 km Unlimited distance Unlimited distance
7
• GDPS/Active-Active is for mission critical workloads that
have stringent recovery objectives that can not be
achieved using existing GDPS solutions
– RTO approaching zero, measured in seconds for unplanned outages
– RPO approaching zero, measured in seconds for unplanned outages
– Non-disruptive site switch of workloads for planned outages
– At any distance
• Active-Active is NOT intended to substitute for local
availability solution such as Parallel Sysplex
Agenda
• Level set
• Concepts
• Sample Scenarios
8
• IMS Replication
• Summary
Terminology
• Active/Active Sites– This is the overall concept of the shift from a failover model
to a continuous availability model
• GDPS active/active continuous availability– This is the formal name of the overall solution under which
IBM will deliver capabilities over a period of time
9
– While IBM currently provides the GDPS active-standby configuration, our future road map includes additional configurations that can lead to full active-active function
• GDPS/Active-Active– The name of the GDPS product which provides, along with
the other products that make up the solution, the capabilities mentioned in this presentation such as workload, replication and routing management and so on. This can be shortened to GDPS/A-A
WorkloadDistributor
Active/Active Sites concept
Transactions
• Two or more sites, separated by
unlimited distances, running the
same applications and having
the same data to provide:
– Cross-site Workload Balancing
– Continuous Availability
– Disaster Recovery
• Data at geographically dispersed
sites kept in sync via s/w
10
Distributor
Replication
sites kept in sync via s/w
replication
Monitoring spans the sites and now
becomes an essential element of the
solution for site health checks,
performance tuning, etc
Workloads are managed by a client and
routed to one of many replicas, depending
upon workload weight and latency
constraints; extends workload balancing to
SYSPLEXs across multiple sites
Active/Active Sites Configurations
• Configurations
1. Active/Standby – GA date 30th June 2011
2. Active/Query – statement of direction
3. Active/Active – intended direction
• A configuration is specified on a workload basis
11
• A configuration is specified on a workload basis
• A workload is the aggregation of these components
– Software: user written applications (eg: COBOL programs) and the middleware run time environment (eg: CICS regions, InfoSphere Replication Server instances and DB2 subsystems)
– Data: related set of objects that must preserve transactional consistency and optionally referential integrity constraints (eg: DB2 Tables, IMS Databases)
– Network connectivity: one or more TCP/IP addresses & ports (eg: 10.10.10.1:80)
Application A, B activeWordload A, B standby
Active/Standby configuration
BBAA
Static RoutingAutomatic Failover
Workload A, B active
Transactions
12
WorkloadDistributor
ReplicationIMS DB2 IMSDB2<<>> <<
queued
>>
This is a fundamental paradigm shift from a failover modelto a continuous availability model
site2site1
Appl B (grey) is in active/query configuration
• using same data as Appl A but read only• active to both site1 & site2, but favor site1• Appl B query routing according to Appl A
latency policy
Transactions
Active/Query configuration (SOD)
BB BB B
AAA
WorkloadDistributor
Appl A (gold) is in active/standby configuration
• performing updates in active site [site2]
13
Replication
M
IMS DB2 IMSDB2<<<<
site2site1
<<<<
[A] latency>5; as “max latency” policy has been exceeded. route
all queries to site2
[A] latency<3; as latency is less than “reset latency” policy, route
more queries to site1
[A] latency=2; as latency is less than “max latency”, follow policy
to skew queries to site1
Read-only or query transactions to be routed to both sites,while update transactions are routed only to the active site
All statements regarding IBM's future direction and intent are subject to change or withdrawal without notice, and represent goals and objectives only.
What S/W makes up a GDPS/Active-Active environment?
• GDPS/Active-Active
• IBM Tivoli NetView for z/OS
– IBM Tivoli NetView for z/OS Enterprise Management Agent (NetView agent)
• IBM Tivoli Monitoring
• System Automation for z/OS
• Multi-site Workload Lifeline for z/OS (SA z/OS)
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• Multi-site Workload Lifeline for z/OS (SA z/OS)
• Middleware – DB2, IMS, CICS…
• Replication Software
– IBM InfoSphere Replication Server for z/OS (DB2)
– IBM InfoSphere IMS Replication for z/OS
• Optionally the Tivoli OMEGAMON XE suite of monitoring products
Integration of a number of software products
GDPS/A-A configuration
Backup Controller
NetView Backup
LLAdvisor Secondary
TEMA
LB 2nd TierSysplex Distrib
LB 2nd TierSysplex Distrib
AAC2LB 1st TierCSM
Network
GDPS Web InterfaceTEP Interface
Primary Controller
NetView Master
LLAdvisor Primary
TEMA
AAC1
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A1 Production 1 A1 Production 2
LLAgent LLAgent
MQ / TCPIP MQ / TCPIP
Workload 1
Active
Workload 3
Active
Workload 1
Active
Workload 3
Active
DB2 Rep IMS Rep DB2 Rep IMS Rep
CICS/DB2
ApplIMS Appl
CICS/DB2
ApplIMS Appl
A2 Production 2 A2 Production 1
LLAgent LLAgent
MQ / TCPIP MQ / TCPIP
Workload 1
Standby
Workload 3
Standby
Workload 1
Standby
Workload 3
Standby
DB2 Rep IMS Rep DB2 Rep IMS Rep
CICS/DB2
ApplIMS Appl
CICS/DB2
ApplIMS Appl
TEMA
Site 1 Site 2DB2 IMS DB2 IMS
A1P2A1P1 A2P1A2P2
S/W Replication
TEMA
• Automation code is an extension on many of the techniques tried and tested in other GDPS products and with many client environments for management of their mainframe CA & DR requirements
• Control code only runs on Controller systems
• Workload management - start/stop components of a workload in a given Sysplex
• Replication management - start/stop replication for a given workload between sites
GDPS/Active-Active (the product)
16
between sites
• Routing management - start/stop routing of transactions to a site
• System and Server management - STOP (graceful shutdown) of a system, LOAD, RESET, ACTIVATE, DEACTIVATE the LPAR for a system, and capacity on demand actions such as CBU/OOCoD
• Monitoring the environment and alerting for unexpected situations
• Planned/Unplanned situation management and control - planned or unplanned site or workload switches; automatic actions such as automatic workload switch (policy dependent)
• Powerful scripting capability for complex/compound scenario automation
Agenda
• Level set
• Concepts
• Sample Scenarios
17
• IMS Replication
• Summary
AA Controller [AAC1]
Primary
AA Controller [AAC2]
Backup
Network
LB 2nd TierSysplex Distrib
LB 1st TierCSM
LB 2nd TierSysplex Distrib
Sample scenario – all workloads active in one site
SASP-compliantRouters
Routing forWKLD 1, 2 & 3
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Site 1 Site 2
A1 Prod-sys [A1P1]
wkld-1 active
wkld-2 active
wkld-3 active
A1 Prod-sys [A1P2]
wkld-1 active
wkld-3 active
A2 Prod-sys [A2P1]
wkld-1 standby
wkld-2 standby
wkld-3 standby
A2 Prod-sys [A2P2]
wkld-1 standby
wkld-3 standby
S/W ReplicationIMS DB2 IMS IMS DB2 IMS
Sys
ple
x-A
1[A
AP
LE
X1]
Sys
ple
x-A
2[A
AP
LE
X2]
AA Controller [AAC1]
Primary
AA Controller [AAC2]
Backup
Sample scenario – both sites active for individual workloads Network
LB 2nd TierSysplex Distrib
LB 1st TierCSM
LB 2nd TierSysplex Distrib
SASP-compliantRouters
Routing forWKLD 1 & 3 Routing for
WKLD 2
19
Site 1 Site 2
A1 Prod-sys [A1P1]
wkld1 active
wkld2 standby
wkld3 active
A1 Prod-sys [A1P2]
wkld1 active
wkld3 active
A2 Prod-sys [A2P1]
wkld1 standby
wkld2 active
wkld3 standby
A2 Prod-sys [A2P2]
wkld1 standby
wkld3 standby
Sys
ple
x-A
1[A
AP
LE
X1]
Sys
ple
x-A
2[A
AP
LE
X2]
S/W ReplicationIMS DB2 IMS IMS DB2 IMS
LB 1st TierCSM
LB 2nd TierSysplex Distrib
LB 2nd TierSysplex Distrib
Planned workload/site switch
TEP Interface GDPS Web Interface
AAC1
primary
AAC2
backup
STOP ROUTINGSTART ROUTING
all data has been drained
continue[click here]
Initiate[click here]
SS Y
Network
20
<<<< >>>>
IMSAppl
[IMS Rep]
WKLD2
WKLD3
AA
PL
EX
1
A1P1
IMSAppl
IMS Rep
WKLD2
A1P2
WKLD1 WKLD1
standby standbyactive active
IMSAppl
WKLD1
IMSAppl
WKLD1
WKLD2
IMS Rep]IMS Rep
WKLD2
WKLD3
AA
PL
EX
2
A2P2 A2P1
IMSDB2IMS IMS DB2 IMS>>
Site1 Site2Note: multiple workloads and needed infrastructure resources are not shown for clarity sake
>> <<
active activestandby standby
LB 2nd TierSysplex Distrib
LB 2nd TierSysplex Distrib
LB 1st TierCSM
Unplanned site failure
TEP Interface GDPS Web Interface
AAC1
primary
AAC2
backup
STOP ROUTINGSTART ROUTING
Network
21
<<<<
IMSAppl
WKLD1
[IMS Rep]
WKLD2
WKLD3
AA
PL
EX
1
A1P1
IMSAppl
WKLD1
IMS Rep
WKLD2
A1P2
IMSDB2IMS
IMSAppl
WKLD1
IMSAppl
WKLD1
WKLD2
IMS Rep]IMS Rep
WKLD2
WKLD3
A2P2 A2P1
active active
IMS DB2 IMS
Site2
Failure Detection Interval = 60 sec
SITE_FAILURE = Automatic
AA
PL
EX
2
Site1Note: multiple workloads and needed infrastructure resources are not shown for clarity sake
Automatic switch
<<
active activestandby standby
>>
logged
2015
60
0
15
30
45
60
GDPS/A-A planned
site switch
GDPS/A-A
unplanned site
switch
GDPS/XRC,
GDPS/GM site
failover
Sw
itch
Tim
e (
secs)
0
60
120
Sit
e F
ail
over
Tim
e (
min
s)
GDPS/A-A – testing results*
min
sec
sec
120min
22
* IBM laboratory results; actual results may vary
• Configuration
– 9 * CICS/DB2 and 1 * IMS workload
– Distance between sites 300 miles (≈500 km)
– Site failure detection interval is 60 seconds
• Planned site switch
– Operations initiated switch of the workloads in a site to
the other site took 20 seconds
– Current GDPS and disk replication will take ≈1-2 hours
• Unplanned site switch
– Automatic switch of failed site workloads to the surviving
site took 15 seconds
– Current GDPS & disk replication will take about ≈1 hour
Agenda
• Level set
• Concepts
• Sample Scenarios
23
• IMS Replication
• Summary
IMS Software-Based Data MirroringInfoSphere IMS Replication
• Unidirectional Replication of IMS data
– Subscription Level Replication
• Transaction consistency
• All or nothing at DB level
• Basic replication monitoring
• TCP/IP for data transmission
• IMS “Capture”
– DB/TM, DBCTL, Batch DL/I, FDBR
IMS
InfoSphere IMS Replication
IMS
24
– DB/TM, DBCTL, Batch DL/I, FDBR
– Capture x’99’ log records
• Increase in log volume due to change data capture records
• IMS “Apply”
– Uses IMS Database Resource Adapter interface
– Parallel Apply
– Conflicts will be detected
• Manual resolution will be required
• Classic Data Architect
– Administration (some administration can be done via z/OS console commands)
– Basic replication monitoring
IMS
Classic DataArchitect
Target IMS Databases
ReplicationMetadata
Administration AdministrationIMSIMS
Source IMS Databases
ReplicationMetadata
BookmarkDatabase
IMS Replication Architecture
25
SOURCE SERVER TARGET SERVER
TCP/IP
IMSLogs
IMS DRA Interface
Administration
One Session Per Subscription
Log
Read/
Merge
UOR
Capture UOR
Analysis
IMSUOR Apply
IMSIMS
Source IMS Databases
Multi-Target Configuration
IMSIMS
Source Server
TargetServer
26
IMSLogs
IMS
IMS
• Multiple Subscriptions
• Each subscription associated with one of the
target servers
• Single server sends updates to appropriate target
Server
TargetServer
IMS
IMS
Sample Two-way Replication Configuration
IMS
Source Server
TargetServer
Workload A Update/Query
Workload A Query
27
IMS
IMS
TargetServer
IMS
Source Server
Query
Workload B Query
Workload B Update/Query
Source Server Details
ReplicationMetadata
IMS
IMSTM / DB
Partner Product
Exit
IMSLogs
IMSLogs
TCP/IP
•User exits to notify server of new IMS
instance
•Merge Waits for Batch
DL/I to complete
28
Change
Stream
Ordering
SOURCE SERVERRECON
IMS Logger Exit
BATCHDL/I
IMSDBCTL
Partner Product
Exit
Capture Services
IMSLogs
Log Info Source IMS Databases
TCP/IP
TCP/IP
DL/I to complete
•Idle IMS regions can
slow processing
Target Server Details
Writer
Services
Staged
Unit-of-Recovery
Data
IMS
DRAthread
WriterApply
Service
ChangeMessages
29
TARGET SERVER
Dependency Analysis
Writer
ServicesService
• Parallelism based on dependency analysis within a subscription
• Database and root key used for analysis
Classic Data Architect – Replication Management
30
Classic Data Architect - Monitoring Throughput
31
Classic Data Architect - Monitoring Latency
32
Adaptive Apply
• Adaptive apply error handling is the default behavior
– Can be set to standard apply, which does not tolerate
conflicts
• If a conflict is detected, the action will be to ignore update
33
• If a conflict is detected, the action will be to ignore update
• Conflicts are:
– Before image mismatch
– Unable to locate segment to process update
• All conflicts are logged in the event log
• Manual resolution will be required
Current Restrictions
• All segments for a DB must have change capture logging enabled and
will be replicated
– Must augment the DBD with the EXIT=(…,LOG) specification
– IMS change capture restrictions
• DEDB FLD calls not supported
34
• Subset Pointers not managed
• ISRT HERE -> ISRT FIRST
• Workload Restrictions
– All logically related DBs must be in the same subscription
– Workload with logically related DBs will be serialized
– UORs with unkeyed or non-unique keyed segments will be serialized
• External load of target DB
– Must be a static image copy
Performance considerations
• Transactional consistency vs. Parallelism
– All updates for a given UR processed as a single transaction during apply
– All transactions involving the same ‘resource’ will be serially processed in commit order
– Running transactions in parallel can have application consistency implications
35
implications
• Increase in log data
• Multiple source IMSs to 1 Apply Target implications
• Internally achieved 53K updates per second
– ~116,000 updates per second when deploying two apply servers
– sustained <2sec latency
– your results may vary
Agenda
• Level set
• Concepts
• Sample Scenarios
36
• IMS Replication
• Summary
Replication Summary
• Asynchronous Replication
– Allows for unlimited distance support
• Low Latency through parallelism
– Allows for almost immediate data availability and low RTO
37
– Allows for almost immediate data availability and low RTO
• Transaction Consistency
– Access with integrity on target system and low RTO
• Subscription independence
– Switch can be at a workload level vs. system level
GDPS Active/Active Summary
• Manages availability at a workload level
• Provides a central point of monitoring & control
• Manages replication between sites
• Provides the ability to perform a controlled
workload site switch
• Provides near-continuous data and systems
availability and helps simplify disaster recovery
38
availability and helps simplify disaster recovery
with an automated, customized solution
• Reduces recovery time and recovery point
objectives – measured in seconds
• Facilitates regulatory compliance management
with a more effective business continuity plan
• Simplifies system resource management
GDPS/Active-Active is the next generation of GDPS
There are multiple GDPS service products under the GDPS solution umbrella to meet various customer requirements for Availability and Disaster Recovery
Continuous Availability of Data
within a Data Center
GDPS/PPRC HM
RPO=0
[RTO secs]
Disaster Recovery Extended Distance
GDPS/GM & GDPS/XRC
RPO secs, RTO<1h
CA Regionally and Disaster Recovery Extended Distance
GDPS/MGM & GDPS/MzGM
RPO=0,RTO mins/<1h
RPO secs, RTO<1h
CA, DR, & Cross-site Workload
Balancing Extended Distance
GDPS/Active-Active
RPO secs, RTO secs
Continuous Availability with
DR within Metropolitan Region
GDPS/PPRC
RPO=0RTO mins / RTO<1h
39
Single Data Center
Applications remain active
Continuous access to data in
the event of a storage outage
[RTO secs]for disk only
Two Data Centers
Rapid Systems D/R w/ “seconds”
of data loss
Disaster Recoveryfor out of region
interruptions
Three Data Centers
High availability for site disasters
Disaster recovery for regional disasters
& RPO secs, RTO<1h
Two Active Data Centers
Automatic workload switch in seconds;
seconds of data loss
RPO – recovery point objective RTO – recovery time objective
RTO mins / RTO<1h(<20km) (>20km)
Two Data Centers
Systems remain active
Multi-site workloads can withstand site
and/or storage failures
Thank You
40
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The following are trademarks or registered trademarks of other companies.
* Registered trademarks of IBM Corporation
IBM*
IBM (logo)*
Ibm.com*
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HyperSwap
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System p*
System z*
Tivoli*
z/OS*
z/VM*
Trademarks
41
* All other products may be trademarks or registered trademarks of their respective companies.
Notes:
Performance is in Internal Throughput Rate (ITR) ratio based on measurements and projections using standard IBM benchmarks in a controlled environment. The actual throughput that any user will experience will vary depending upon considerations such as the amount of multiprogramming in the user's job stream, the I/O configuration, the storage configuration, and the workload processed. Therefore, no assurance can be given that an individual user will achieve throughput improvements equivalent to the performance ratios stated here.
IBM hardware products are manufactured from new parts, or new and serviceable used parts. Regardless, our warranty terms apply.
All customer examples cited or described in this presentation are presented as illustrations of the manner in which some customers have used IBM products and the results they may have achieved. Actual environmental costs and performance characteristics will vary depending on individual customer configurations and conditions.
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Information about non-IBM products is obtained from the manufacturers of those products or their published announcements. IBM has not tested those products and cannot confirm the performance, compatibility, or any other claims related to non-IBM products. Questions on the capabilities of non-IBM products should be addressed to the suppliers of those products.
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