Bad Things Happen to Good People: How to Minimize the Pain

Transcription

1 NEODBUG November 21 st, 2013 Bad Things Happen to Good People: How to Minimize the Pain DB2 for Linux, UNIX, and Windows Kelly Schlamb Executive IT Specialist, Worldwide Information Management Technical Sales IBM Canada Ltd.

2 Disclaimer Copyright IBM Corporation All rights reserved. U.S. Government Users Restricted Rights - Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. THE INFORMATION CONTAINED IN THIS PRESENTATION IS PROVIDED FOR INFORMATIONAL PURPOSES ONLY. WHILE EFFORTS WERE MADE TO VERIFY THE COMPLETENESS AND ACCURACY OF THE INFORMATION CONTAINED IN THIS PRESENTATION, IT IS PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. IN ADDITION, THIS INFORMATION IS BASED ON IBM'S CURRENT PRODUCT PLANS AND STRATEGY, WHICH ARE SUBJECT TO CHANGE BY IBM WITHOUT NOTICE. IBM SHALL NOT BE RESPONSIBLE FOR ANY DAMAGES ARISING OUT OF THE USE OF, OR OTHERWISE RELATED TO, THIS PRESENTATION OR ANY OTHER DOCUMENTATION. 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 ANY AGREEMENT OR LICENSE GOVERNING THE USE OF IBM PRODUCTS AND/OR SOFTWARE. IBM's statements regarding its plans, directions, and intent are subject to change or withdrawal without notice at IBM's sole discretion. Information regarding potential future products is intended to outline our general product direction and it should not be relied on in making a purchasing decision. The information mentioned regarding potential future products is not a commitment, promise, or legal obligation to deliver any material, code or functionality. Information about potential future products may not be incorporated into any contract. The development, release, and timing of any future features or functionality described for our products remains at our sole discretion. IBM, the IBM logo, ibm.com, Information Management, DB2, DB2 Connect, DB2 OLAP Server, purescale, System Z, Cognos, soliddb, Informix, Optim, InfoSphere, and z/os are trademarks or registered trademarks of International Business Machines Corporation in the United States, other countries, or both. If these and other IBM trademarked terms are marked on their first occurrence in this information with a trademark symbol ( or ), these symbols indicate U.S. registered or common law trademarks owned by IBM at the time this information was published. Such trademarks may also be registered or common law trademarks in other countries. A current list of IBM trademarks is available on the Web at Copyright and trademark information at Other company, product, or service names may be trademarks or service marks of others. 2

3 Logging and Recovery October 28, 2013

4 What Could Possibly Go Wrong? Famous Last Words. As the Boy Scouts say "Be prepared!" Database server goes down (planned or unplanned) Underlying storage becomes unusable Site disaster Database is accidentally dropped Hardware component failure Table is accidentally dropped or data deleted Table space is accidentally dropped 4

5 Develop a Recovery Plan Some questions to ask yourself when developing a recovery plan Does the database need to be recoverable? What are your RPO and RTO requirements? Recovery Point Objective how much data loss is acceptable, if any, if a major incident occurs? Recovery Time Objective what is an acceptable length of time to perform the recovery while the system is unavailable? How frequent do the backup operations need to be? How much storage space can be used for backups and archived logs? Where do you want the backups and archived logs to go? Will table space level backups be sufficient, or will full database backups be necessary? Do the backups need to be automated? Is high availability (HA) a consideration? Is off-site disaster recovery (DR) a consideration? 5

6 Logging & Log File Management Recommendations Use archive logging (not circular logging) for production environments Provides better recovery characteristics (lower RPO) Permits use of online backups (better availability) and table space level backups (more granular) Can setup two archive log paths for best protection Include logs in backup images (default behavior) Allows restoring of an online backup if all you have is the backup image (e.g. disaster recovery) Configure mirrored logging on separate file systems Protects against file system corruption or accidental deletion of log files For archive logging, consider using automated log file management Choose how long to retain recovery objects like backups and archived logs and when to automatically prune them See NUM_DB_BACKUPS, REC_HIS_RETENTN, and AUTO_DEL_REC_OBJ database configuration parameters 6

7 Backup & Recovery Various methods and options available for backing up and recovering the data in your databases Offline or online backups Database or table space backups Split mirror / flash copy backups Incremental backups Rebuild database from table space backup images Backup compression As database size increases, consider using more frequent, online table space level backups Built-in autonomics for backup command provides optimal values for number of buffers, buffer size, and parallelism Values calculated based on amount of utility heap memory available, the number of processors available, and the database configuration Automatic backup maintenance can be enabled 7

8 Automatic Backups Automatic database backups simplify backup management by ensuring that recent full backup of database is performed The need to perform a backup is based on one or more of the following criteria You have never created a full database backup The time elapsed since the last full backup is more than a specified number of hours The transaction log space consumed since the last backup is more than a specified number of 4 KB pages (in archive logging mode only). Backups can be configured to be offline or online Supports disk, tape, TSM, and vendor DLL media types Feature is enabled/disabled by using auto_db_backup and auto_maint database configuration parameters Policies can be defined via SYSPROC.AUTOMAINT_SET_POLICY and SYSPROC.AUTOMAINT_SET_POLICYFILE stored procedures 8

9 Incremental Backups Incremental backups contain data changed since previous backups (depending on the type of backup incremental or delta) In addition to data, each incremental backup image also contains all of the database metadata Incremental (cumulative) backup image Contains all database data that has changed since the most recent, successful, full backup operation Cumulative because a series of incremental backups taken over time will each have the contents of the previous incremental backup image Delta backup image Contains a copy of all database data that has changed since the last successful backup (full, incremental, or delta) of the table space in question Combinations of database and table space incremental backups are permitted, in both online and offline modes of operation To restore a database or table space to a consistent state, the recovery process must begin with a consistent image of the object to be restored, followed by the application of the appropriate incremental backup images TRACKMOD database configuration parameter must be set to YES 9

10 Incremental Backups: Examples Weekly full backups, daily incremental (cumulative) backups: Weekly full backups, daily delta backups: Weekly full backups (Sunday), incremental (cumulative) backup half-way through week, delta backups all other days: Recovery required (prior to Saturday's delta being taken): 10

11 Database Rebuild Automatic restoring of necessary backup images Rebuild a database from table space backup images Means no longer having to take as many full database backups, which is becoming less possible as databases grow in size Instead, take more frequent table space backups In a recovery situation, if you need to bring a subset of table spaces online faster than others, you can do a partial database rebuild May also be used for Creating a separate database for QA purposes Data recovery purposes Can choose which table spaces to restore as part of the rebuild All table spaces in the database at a time that the backup was taken All table spaces included in a selected table space backup A specific list of table spaces specified as part of the restore command All table spaces except those in the specific list provided 11

12 Database Disaster Recovery using Rebuild Necessary table spaces will be restored automatically based on recovery history data SYSCATSPACE SalesDB SMS01 Recovery History File 2 DMS01 DMS02 Backup Database SALESDB Backup TS DMS01 Backup TS DMS02 Backup TS DMS01 SUN MON TUE WED THU FRI SAT 3 1 Database Fails! 1. RESTORE DB SALESDB REBUILD WITH ALL TABLESPACES IN DATABASE TAKEN AT <Friday> (DB2 restores Friday, Sunday and Thursday) 2. ROLLFORWARD DB SALESDB TO END OF LOGS AND STOP 12

13 Database Recovery - Rebuild from Table Space Backups Database recovery using multiple table space backups SYSCATSPACE SalesDB SMS01 Recovery History File Backup TS DMS02 DMS01 2 Backup TS SMS01 SYSCATSPACE Backup TS DMS02 DMS01 DMS01 Backup TS DMS01 DMS02 SUN MON TUE WED THU FRI SAT 3 1 Database Fails! 1. RESTORE DB SALESDB REBUILD WITH ALL TABLESPACES IN DATABASE TAKEN AT <Friday> (DB2 restores Friday, Tuesday and Thursday) 2. ROLLFORWARD DB SALESDB TO END OF LOGS AND STOP 13

14 Database Partial Copy using Rebuild Can create a database copy with a subset of table spaces SalesDB SalesDB SYSCATSPACE SMS01 SYSCATSPACE 2 DMS01 DMS02 DMS01 Backup Database SALESDB Backup TS DMS01 Backup TS DMS02 Backup TS DMS01 SUN MON TUE WED THU FRI SAT 1 Copy for testing OR 1. RESTORE DB SALESDB REBUILD WITH TABLESPACE(SYSCATSPACE,DMS01) TAKEN AT Friday (DB2 Restores Friday, and Sunday (just SYSCATSPACE TS) RESTORE DB SALESDB REBUILD WITH ALL TABLESPACES IN DATABASE EXCEPT TABLESPACE(SMS01,DMS02) TAKEN AT Friday 2. ROLLFORWARD DB SALESDB TO END OF LOGS AND STOP 14

15 Transportable Schemas Efficient schema movement between databases Using a backup image as the source, allows you to copy a set of table spaces and SQL schemas from one database into another A database schema must be transported in its entirety If a table space contains both the schema you want to transport, as well as another schema, you must transport all data objects from both schemas These self contained (from a table space perspective) sets of schemas that have no references to other database schemas are called transportable sets Restore will do multiple operations under the covers Restore SYSCATSPACE and specified table spaces from backup image Roll them forward to a point of consistency Validate the schemas specified Transfer ownership of the specified table spaces (including containers) to the target database Recreate the schema in the target database 15

16 Transportable Schemas: Example Not a valid transportable set Valid transportable set The database contains the following valid transportable sets: mydata1: schema1 + schema2 mydata2 + myindex: schema3 multidata1 + multiuser2 + multiindex1: schema4 + schema5 Any combination of the above transportable sets To Move All Table Spaces: restore db old_db \ tablespace ( mydata1, mydata2, myindex, multidata1, multiindex1, multiuser2 )\ schema ( schema1, schema2, schema3, schema4, schema5 ) transport into new_db 16

17 DB2's Dropped Table Recovery Feature Recover the contents of a dropped table using DB2's table space restore and rollforward operations When rolling forward through the drop of the table, the data is exported prior to the replay of the drop Requires that the table space be enabled for dropped table recovery Enabled by default at table space creation time When a table is dropped, an entry is made in the transaction log files as well as in the recovery history file You can recover a dropped table by doing the following: 1. Identify the dropped table by invoking the LIST HISTORY DROPPED TABLE command 2. Restore a database- or table space-level backup image taken before the table was dropped 3. Create an export directory to which files containing the table data are to be written 4. Roll forward to a point in time after the table was dropped (or to end of logs) by using the RECOVER DROPPED TABLE parameter on the ROLLFORWARD DATABASE command 5. Re-create the table by using the CREATE TABLE statement from the recovery history file 6. Import the table data that was exported during the rollforward operation into the table 17

18 Proactive Checking of Database and Recovery Objects db2dart Database analysis and reporting tool Examines database for architectural correctness INSPECT Database inspection command Inspects database for architectural integrity Can be run while the database is online db2ckbkp Check backup command Test the integrity of a backup image db2cklog Check archive log file validity command Check the validity of archive log files in order to determine whether or not the log files can be used during rollforward recovery of a database or table space 18

19 IBM DB2 Recovery Expert Granular and Flexible Data Recovery Part of the DB2 Advanced Recovery Feature Faster Simplifies and optimizes database recovery by reducing disruption during the recovery process DBAs can quickly restore or correct erroneous data Log Analysis enables organizations to monitor changes that allow for quick recovery Smarter Provides intelligent analysis of DB2 and DB2 recovery assets to find the most efficient recovery path Simpler Facilitates process of rebuilding data assets to a specified point in time, often without taking operations offline AFS is establishing a disaster recovery policy with our Vision Application. DB2 Recovery Expert provides us with the functionality to roll back both databases to a point where the tables are consistent. This will help us meet 100% of our needs for this project. The product itself is awesome and WEB UI is very nice. -Kirk B. Spadt, Principal Architect, Automated Financial Systems 19

20 IBM DB2 Merge Backup (MBK) Merge full DB2 backups with DB2 incremental/delta backups to build a new up-to-date full DB2 backup image Eliminates the need to take DB2 full backups Part of the DB2 Advanced Recovery Feature Use online or offline, and table space or database backup images Split out table space backup images from a full backup image Run MBK on the database server or on a standalone remote machine Benefits include Reduce backup intensive resources on the database server Reduce backup storage footprint Eliminate full DB2 backups by backing up only what needs to be backed up Reduce number of objects required during recovery Simplify recovery process through restore of up-to-date full backup images Speed up recovery with up-to-date more recent full backup images 20

21 Merge Backup Overview Time Full DB2 Backup from DB2 DB2 Incremental Backups Merge Backup Processing Full DB2 Backup from MBK 21

22 Eliminate the Need to Take Full DB2 Backups MBK Full DB2 Backup Full DB2 Backup MBK MBK... Full DB2 Backup Full DB2 Backup 22

23 High Availability and Disaster Recovery October 28, 2013

24 What Does Downtime Mean To Your Business? Negative Negative Press Press Damaged Damaged Reputation Reputation Lost Lost Revenue Revenue Loss Loss of of Market Market Share Share to to Competitors Competitors Availability % 99.99% Downtime per Year 5 minutes 52 minutes Reduced Reduced IT/Employee IT/Employee Productivity Productivity 99.9% 8 hours, 45 minutes Customer Customer Dissatisfaction Dissatisfaction 99% 95% 3.65 days days Reduced Reduced End-User End-User Productivity Productivity 64% of organizations require that their databases deliver a minimum of 99.99% or better uptime for their most mission critical applications * Breach Breach of of SLA/Contract SLA/Contract Reduced Reduced Company/ Company/ Shareholder Shareholder Value Value 24 * ITIC Paper "Two-Thirds of Corporations Now Require 99.99% Database Uptime, Reliability ", Laura DiDio, July 10 th, 2013

25 DB2 Has the Right Solution to Meet Your HA Needs HADR CF CF HADR purescale Integrated Clustering 25

26 High Availability and/or Disaster Recovery Options Server failover Shared disk or remote disk mirroring HADR High Availability and/or Disaster Recovery Easy to set up and manage Automatic failover with TSA integration Fast failover Q-Replication Flexible can handle database subsets Active/Active Asynchronous purescale (Active / Active) Continuous Availability Load Balancing Easy to set up and manage 26

27 Server-Based Failover tx tx DB2 ships with an integrated TSA cluster manager Node Failure Detection Disk takeover IP takeover Restart DB2 Management framework included to keep the cluster topology in sync Active Server 27

28 Storage Replication Uses remote disk mirroring technology Maximum distance between sites is typically 100s of km (for synchronous, 1000s of km for asynchronous) For example: IBM Metro Mirror, EMC SRDF Transactions run against primary site only, DR site is passive If primary site fails, database at DR site can be brought online All data and logs must be mirrored to the DR site Synchronous replication guarantees no data loss Writes are synchronous and therefore ordered, but consistency groups are still needed If failure to update one volume, don t want other volumes to get updated (leaving data and logs out of sync) 28

29 High Availability Disaster Recovery (HADR) Provides local High Availability and/or Disaster Recovery Keeps two copies of a database in sync with each other on two different servers Simple to setup and manage DB2 9.5 adds an integrated cluster manager for automatic failover DB2 10 adds multiple standbys, time delay and log buffering to handle network spikes 29

30 HADR: DB2 Delivers Fast Failover at Low Cost Redundant copy of the database to protect against site or storage failure Support for Rolling Upgrades Failover typically under 15 seconds Example: Real SAP workload, 600 SAP users database available in 11 sec. 100% performance after primary failure Automatic Client Reroute Client application transparently resumes on Standby tx tx Network Connection HADR Keeps the two servers in sync tx tx TSA for server monitoring Built in cluster manager Monitors primary & performs takeover Standby Server Primary Server Standby Server 30

31 HADR Synchronization Modes Synchronous, Near Synchronous, Asynchronous and Super Asynchronous HADR send() receive() HADR log writer Asynchronous Near- Synchronous Commit Request log file Synchronous log file Super Asynchronous Commit Succeeded 31

32 HADR Failover Single command called "TAKEOVER" Change the standby into a primary Switch the roles of a healthy primary-standby pair No db2start / restart database / rollforward etc. Integrated TSA provides heartbeat monitoring & automated TAKEOVER Set up for you during DB2 installation Use a network tiebreaker to avoid split brain scenarios Configuration is available in this whitepaper Automatic client re-route (ACR) provides transparent failover And will rerun the statement that was running when the failure occurred as long as it s the first statement of a transaction with no data yet returned 32

33 HADR Multiple Standbys Primary Any sync mode Super async mode Principal Standby Auxiliary Standby Super async mode Auxiliary Standby Allows for one standby for high availability and up to two other standbys for disaster recovery Rolling fix pack updates of standbys and primary without losing HA Reads on standby supported on all standbys TSA Automation for takeover is only to Principal Standby Takeover (forced and non-forced) supported from any standby After takeover, configuration parameters on new primary s standbys will be changed automatically so they point to the new primary 33

34 HADR Log Spooling on the Standby When enabled, allows the standby to spool log records arriving from the primary Decouples log replay on the standby from receiving of the log data from the primary Supported with any synchronization mode Primary Standby Any sync mode Spooled logs on standby 34 34

35 HADR Time-Delayed Apply on the Standby Helps recover from application errors For example, accidental deletion of important table data Must be noticed before time delay on standby results in change being replayed Enabled via the new HADR_REPLAY_DELAY database configuration parameter Specifies a delay in seconds for applying changes on a standby A value of 0 means no time delay (the default) Primary Standby super async mode Spooled logs on standby 35

36 Q Replication High-throughput, low latency logical data replication Distance between sites can be up to thousands of km Asynchronous replication Includes support for: Delayed apply Multiple targets Replicating a subset of data Data transformation DR site can be active Bi-directional replication is supported for updates on both primary and DR sites 36

37 Q Replication Each message represents a transaction Highly parallel apply process Differentiated conflict detection and resolution 37

38 Continuous Availability Using Q Replication Q Replication provides a solution for continuous availability where the active secondary system is also available for other applications 38

39 Introducing DB2 purescale Extreme capacity Buy only what you need, add capacity as your needs grow Application transparency Avoid the risk and cost of application changes Continuous availability Deliver uninterrupted access to your data with consistent performance Learning from the undisputed Gold Standard... System z 39

40 DB2 purescale Scalability, Performance, and Always Available Transactions DB2 purescale Robust infrastructure for OLTP workloads Provides improved availability, performance and scalability Application transparency Scales to >100 members Leverages z/os cluster technology Highlights of purescale enhancements in DB Rich disaster recovery options, now including integrated HADR support Backup and restore between purescale and non-purescale environments Online fix pack updates Add members online for additional capacity Included in Advanced Workgroup and Advanced Enterprise editions 40

41 DB2 purescale Architected for extreme scale and availability Clients Multiple DB2 members for scalable and available database environment Client application connects into any DB2 member to execute transactions Automatic workload balancing Shared storage for database data and transaction logs CF CS Primary CF 41 CS Member CS Member Cluster Interconnect Logs Logs Logs Logs Database CS Member Shared Storage DB2 purescale Cluster (Instance) CS Member CF CS Secondary CF Cluster caching facilities (CF) provide centralized global locking and page cache management for highest levels of availability and scalability Duplexed, for no single point of failure High speed, low latency interconnect for efficient and scalable communication between members and CFs DB2 Cluster Services provides integrated failure detection, recovery automation and the clustered file system

42 Log Log Log Log Log Scale with Ease Scale up or out without changing your applications Efficient coherency protocols designed to scale without application changes Applications automatically and transparently workload balanced across members Up to 128 members Member Member Member Member Add member online Member Without impacting availability Members can be added while cluster remains online CF CF Without administrative complexity No data redistribution required DB2 purescale is the only solution we found that provided near linear scalability... It scales 100 percent, which means when I add servers and resources to the cluster, I get 100 percent of the benefit. Before, we had to oversize our servers, and used only percent of the available capacity so we could scale them when we needed. -- Robert M. Collins Jr. (Kent), Database Engineer, BNSF Railway Inc. 42

43 Online Recovery from Failures DB2 purescale design point is to maximize availability during failure recovery processing X When a database member fails, only in-flight data remains locked until member recovery completes In-flight = data being updated on the failed member at the time it failed CF CF Target time to availability of rows associated with in-flight updates on failed member in seconds We pulled cards, we powered off systems, we uninstalled devices, we did everything we could do to make the cluster go out of service, and we couldn t make it happen. -- Robert M. Collins Jr. (Kent), Database Engineer, BNSF Railway Inc. % of Data Available Database member failure Only data in-flight updates locked during recovery Time (~seconds)

44 Stealth System Maintenance Allows DBAs to apply system maintenance without negotiating an outage window Example: Upgrade the OS in a rolling fashion across the cluster Procedure: 1. Drain (a.k.a. Quiesce) Wait for transactions to end their life naturally; new transactions routed to other members 2. Remove & maintain 3. Reintegrate into cluster Workload balancing starts sending it work as a least loaded machine 4. Repeat until done Single Database View DB2 DB2 DB2 DB2 44

45 Rolling Database Fix Pack Updates New in DB Transparently install purescale fix packs or perform system maintenance in an online rolling fashion No outage experienced by applications Single installfixpack command run on each member/cf for fix pack update Quiesces member Existing transactions allowed to finish (configurable timeout) New transactions sent to other members Installs binaries Updates instance Member still behaves as if running on previous fix pack level Unquiesces member CF CF Final installfixpack command to complete and commit updates Instance now running at new fix pack level 45

46 Rolling Fix Pack Updates (cont.) Transactions routed away from member undergoing maintenance, so no application outages experienced. Workload balancing brings work back after maintenance finished 6 7 Cluster is effectively running at: GA FP1 > installfixpack installfixpack check_commit check_commit > installfixpack commit_level Cluster not running at new level until commit is performed Member Member Member Code level: GA FP1 Code level: GA FP1 Code level: GA FP1 3 > installfixpack installfixpack online online 4 > installfixpack installfixpack online online 5 > installfixpack installfixpack online online CF S CF P Code level: GA FP1 Code level: GA FP1 1 > installfixpack installfixpack online online 2 > installfixpack installfixpack online online 46

47 Disaster Recovery Options for purescale Variety of disaster recovery options to meet your needs HADR (new in DB2 10.5) Storage Replication Q Replication InfoSphere Change Data Capture (CDC) Geographically Dispersed purescale Cluster (GDPC) Manual Log Shipping 47

48 Geographically Dispersed purescale Clusters (GDPC) A stretch or geographically dispersed purescale cluster spans two sites At distances of tens of km Active/active DR, where half of the cluster is at site A, other half at site B Enables a level of DR support suitable for many types of disasters Supported for AIX (using InfiniBand) and RedHat Linux (using 10 Gigabit Ethernet) Both sites active and available for transactions during normal operation On failures, client connections are automatically redirected to surviving members Applies to both individual members within sites and total site failure Tens of km M1 M3 CF P CF S M2 M4 Site A Workload fully balanced Site B Tens of km M1 M3 CF P CF S M2 M4 Site A Site B Workload rebalanced on hardware failure Tens of km M1 M3 CF P CF S M2 M4 Site A Site B Workload rebalanced on site failure 48

49 HA & DR Scenarios October 28, 2013

50 Local Cluster Failover DB2 automation with built-in cluster manager HA Cluster Primary Database Local Standby Database DB1 Pros: Inexpensive local failover solution Protection from software and server failure DB2 9.5 integrated TSA cluster manager Cons: No protection from disk failure No protection from site failure Failover times vary from 5 to 15 minutes 50

51 HADR Local or Remote with Read on Standby Primary Connection HADR Cluster Primary Database Standby Database DB1 DB1 a Read only Pros: Inexpensive local failover or DR solution Protection from software, server, storage, and site failures Simple to setup and monitor Failover time in the range of 30 sec Reporting on standby without increase in failover time 51 Cons: Two full copies of the database (a plus from a redundancy perspective) Only read transactions can run on standby

52 HADR With Disk Mirroring to Remote DR Site Primary Connection HADR Cluster Primary Database Automatic client reroute Local Standby Database Disaster Recovery Site DB1 DB1 a Remote Disk Mirror Technology DB1 aa Pros: Very fast local failover with DR capability Protection from software, server, storage, and site failures Local failover time in the range 30 seconds Cons: Three full copies of the database (a plus from a redundancy perspective) More costly than HADR for just DR 52

53 HADR With Multiple Standby s (DB2 10) Primary Connection HADR Cluster Primary Database Automatic client reroute Local Standby Database Disaster Recovery Site DB1 DB1 a Remote Standby DB1 aa Pros: Very fast local failover with DR capability Protection from software, server, storage, and site failures Allows for time delay on auxiliary standbys Local failover time in the range 30 seconds 53 Cons: Three full copies of the database (a plus from a redundancy perspective) Super Async only for DR site

54 Q Replication Site A Primary Database Primary Connection Read/Write write on standby Remote Standby Multiple alternate standby servers Site C Site B DB1 Q-based SQL replication to logical standby s DB2 DB3 Pros: Protected from software, server, storage, and site failures Failover time is instant Standby can be full or subset and is fully accessible (read and/or write) Multiple standby servers Cons: More complex to setup and monitor (but more flexibility) vs. HADR Asynchronous 54

55 High Availability Disaster Recovery (HADR) Options Local HA fast failover with server and storage protection Site A Server A Primary Server B Standby Disaster Recovery server, storage and site protection Site A Server A Any Distance Server B Site B Primary Standby Both fast local failover with server, storage and site protection Any Distance Site A Server A Server B Server C Site B Primary Standby Standby 55

56 HADR with Replication Best Practice for HA and DR HADR Pairs with Replication Site A Server A Server B Q Replication Any Distance Server C Server D Site B Primary Standby Active Standby Delivers: Fast Local Failover Active / Active DR Rolling patch upgrades Rolling version upgrades Online database on-disk modifications Schema modifications online/rolling Can replace HADR at each site with purescale for even better HA 56

57 DB2 purescale Availability Options Local only Online recovery, active-active, protection from server failure Site A CF Member 1 Member 2 CF Geographically dispersed cluster Online recovery, active-active, protection from server, storage and site failure Site A CF Member 1 Member 2 < 80km Member 3 Member 4 CF Site B Local purescale plus DR replication Online recovery, active-active, protection from server, storage and site failure 57 Site A CF Member 1 Member 2 CF Any distance Disk Replication or IBM Replication Server CF Member 1 Member 2 CF Site B

58 DB2 purescale Availability Option in DB DB supports HADR with purescale Online recovery, protection from server, storage and site failure Easy to set up and manage Any distance (ASYNC or SuperAsync) Site A CF Member 1 Member 2 CF Any distance HADR CF Member 1 Member 2 CF Site B 58

59 HA & DR Summary When it comes to HA and DR, one size does not fit all There are many availability options, each with their own advantages Server failover HADR Q-Replication purescale More likely a combination of several of the above Choose the one that best suits your deployment Determine the right solution considering Cost (hardware/software/network/site) Availability requirements Management costs Application requirements 59

60 Kelly Schlamb Executive IT Specialist, Worldwide Information Management Technical Sales IBM Canada Ltd. 60