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SQL Saturday 2009 – Portland, Oregon
HA cover




Copyright 2009 – Database Architechs
       www.dbarchitechs.com
Agenda
What is High Availability?

How do you assess your HA Requirements?

What are the MS SQL Server related options for...
Test

1. What is the quickest way to test if your SQL Server Clustering
   configuration is failing over properly?

2. Wha...
What is Availability?
         Application
         Availability


                                                       ...
The cost of Un-Availability
Airline Reservation Systems - $67K to $112K per hour

ATM Service Fees - $12K to $17K per hour...
Across all layers of your systems
Network
   Application
     Middleware
        Database
                                ...
Availability across planned operation

              100%
                                                                ...
Availability Continuum
                                            Characteristic               Availability Range

   Ext...
Applications and Availability                     Extreme Availability
                                                   ...
What do you need?
It’s as simple as 1, 2, 3 +

    Step One – Launch of a brief “Phase 0” HA Assessment

    Step Two – Co...
Assessing HA with Primary Variables
0%                                                                         100%
      ...
Development Methodology
                                     “With High Availability built in”
          Assessment
      ...
Spiral/Rapid Methodology
                                                  Iterative approach                             ...
Valid High Availability Options

               Disk     Other   Cluster          Data        SQL         DB         Log
 ...
MSCS Cluster Services

                                                               C:
                                 ...
SQL
                     SQL Clustering
Connections                                                                   COLT...
Data Replication
                                                      Can be used as a Warm Standby
                     ...
Database Mirroring
             Client          Client     Client      Client


                                Network

 ...
Database Mirroring
                     with DB Snapshots
     SQL Server 2008                                 SQL Server ...
Log Shipping
                                        “Source”
                                      SQL Server 2008       ...
RAID Disk I/O Summary

    RAID Level    Fault Tolerance           Logical        Physical I/Os       Logical         Phys...
Fault Tolerance and SQL DB Files
                                         Description                       Fault Toleranc...
Example DB data files configuration
                                                                     E:
              ...
Decision Tree approach

                      Condition/Question
          Case A Case B Case C Case D                    ...
Decision-Tree Path Traversal

                                                                    SQL
                    ...
Decision-Tree: ASP Questions 1-3
1
                What % of availability must your application have?
A% <= 70%           ...
Decision-Tree: ASP Questions 4-6
4
            How long does it take to get the application back online?
    Very Long    ...
Decision-Tree: ASP Questions 7-9
7
                 How often is scheduled maintenance required?
    Very Often          O...
Decision-Tree: ASP Question 10
10
          What is the estimated cost of the HA Solution (budget)?
     C$ < $10K        ...
Basic “one-two” Punch approach

1                        Build the proper foundation first

      Hardware/Network        ...
ASP – Scenario #1 with SQL Clustering
                                                                                    ...
Log Shipping
                                        “Source”
                                      SQL Server 2000       ...
North America
                                                        (Reporting & “warm/hot” spare)
                     ...
SQL Server 2000
                     Central Publisher                       SQL Server 2000
Subscription          (defaul...
Central Publisher
SQL Server 2000                                              SQL Server 2000
Subscription      Remote Di...
Data Access     Latency   Autonomy
                                  Distributing Data
                                   ...
Foundation, Foundation, Foundation
                   Piecing it together
Hardware/Network   Disk Backups             Vend...
ROI
Calculati
   on




            Copyright 2009 – Database Architechs
                   www.dbarchitechs.com
Database Mirroring

Transparent Client Redirect
                                                  Network

               ...
20FIG30

SQL Server 2005 Database Mirroring
20FIG31
SQL Server 2008 Database Mirroring
16




                                     43
Copyright 2009 all rights reserved
Database Mirroring with
                 DB Snapshot
  SQL Server 2005                                                   S...
Snapshot
                            Source Data                  Users
                               Pages
             ...
Instance: SQL2008xyz                    PH Topology With Snapshots
                                   Endpoint Name: “endp...
Publisher                                     The Combo Pack
SQL Server 2008   SQL Server 2008



  Principal           Mi...
Restart
                                 Stage




                                 Rolled Forward
                       ...
Performance and Tuning
     counts in HA
SQL SHOT – MS SQL Server
Questions

Is there any time left????




    Copyright 2009 – Database Architechs
           www.dbarchitechs.com
SQL Server Resources




                                           Stop!
    Copyright 2009 – Database Architechs
       ...
Fail-Over via Move Group




    ANSWER to question #1
       Copyright 2009 – Database Architechs
              www.dbarc...
Distributed Transactions

                                                     “Primary Location”
                        ...
SQL Server High Availability
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SQL Server High Availability

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Transcript of "SQL Server High Availability"

  1. 1. SQL Saturday 2009 – Portland, Oregon HA cover Copyright 2009 – Database Architechs www.dbarchitechs.com
  2. 2. Paul Bertucci • Founder Database Architechs – www.dbarchitechs.com – Specializing in HA, Database Design, Data Architecture, Data Replication, and P&T for SQL Server, Sybase, DB2 and Oracle – Over 28+ years experience in Data Base industry • Co-Author of SQL Server 2000 Unleashed! (SAMS) • Co-Author of SQL Server 2005 Unleashed! (SAMS) • Co-Author of SQL Server 2008 Unleashed! (SAMS) – Summer 2009 ! • Co-Author of ADO.NET in 24 hours (SAMS) • Author MS SQL Server High Availability (SAMS) • Author Sybase Performance & Tuning • Author Sybase Physical DB Design • Veritas SQL Server Performance Series • Former Chief Data Architect Symantec Corporation • Current Chief Architect Autodesk Corporation pbertucci@dbarchitechs.com Copyright 2009 – Database Architechs www.dbarchitechs.com
  3. 3. Agenda What is High Availability? How do you assess your HA Requirements? What are the MS SQL Server related options for HA? How each option delivers HA… Performance and Tuning is critical too – SQL Shot! Q&A Copyright 2009 – Database Architechs www.dbarchitechs.com
  4. 4. Test 1. What is the quickest way to test if your SQL Server Clustering configuration is failing over properly? 2. What is the SQL Server feature in SQL Server 2005/2008 that replaces Log Shipping? Copyright 2009 – Database Architechs www.dbarchitechs.com
  5. 5. What is Availability? Application Availability Failure causes: Planned Unplanned - Human Uptime - Hardware Downtime Downtime - Software Recoverable Disaster Copyright 2009 – Database Architechs www.dbarchitechs.com
  6. 6. The cost of Un-Availability Airline Reservation Systems - $67K to $112K per hour ATM Service Fees - $12K to $17K per hour Brokerage (Retail) - $5.6M to $7.3M per hour What is your cost of downtime? Copyright 2009 – Database Architechs www.dbarchitechs.com
  7. 7. Across all layers of your systems Network Application Middleware Database HARDWARE Operating System Network Components Servers Disk Systems Memory Copyright 2009 – Database Architechs www.dbarchitechs.com
  8. 8. Availability across planned operation 100% Availability Goals 90% Availability (%) Feb 14-28 Mar 1 – Apr 15 Apr 16 – 20 Starting Date Date of Failure Days Hours Minutes MBU (minutes) TU Avail % Period 1 2/14/2008 2/28/2008 15.00 24.00 60.00 21600.00 38.00 99.82407 Period 2 3/1/2008 4/15/2008 46.00 24.00 60.00 66240.00 68.00 99.89734 Period 3 4/16/2008 4/20/2008 5.00 24.00 60.00 7200.00 442.00 93.86111 Overall 2/14/2008 4/20/2008 66.00 24.00 60.00 95040.00 548.00 99.4234 Copyright 2009 – Database Architechs www.dbarchitechs.com
  9. 9. Availability Continuum Characteristic Availability Range Extreme Availability Near zero downtime! (99.5% - 100%) High Availability Minimal downtime (95% - 99.4%) Standard Availability With some downtime (83% - 94%) tolerance Acceptable Availability Non-critical Applications (70%-82%) Marginal Availability Non-production Applications (up to 69%) Availability Range describes the percentage of time relative to the “planned” hours of operations 8,760 hours/year | 168 hours/week | 24 hours/day 525,600 minutes/year | 7,200 minutes/week | 1,440 minutes/day Copyright 2009 – Database Architechs www.dbarchitechs.com
  10. 10. Applications and Availability Extreme Availability High Availability ATM Zero Standard Availability Planned eCommerce 911 Downtime email Acceptable Availability Inventory Accounting Mgmt Marginal Availability HR Marketing Mailers Zero Unplanned Downtime Five 9’s (99.999%) ~ 6 minutes/year downtime Copyright 2009 – Database Architechs www.dbarchitechs.com
  11. 11. What do you need? It’s as simple as 1, 2, 3 + Step One – Launch of a brief “Phase 0” HA Assessment Step Two – Complete an HA Primary Variables gauge Step Three – Match your need to the optimal HA solution Step + (optional) – Determine the ROI of the HA solution Copyright 2009 – Database Architechs www.dbarchitechs.com
  12. 12. Assessing HA with Primary Variables 0% 100% Uptime Requirement Long Short Time to Recover High Low Tolerance of Recovery Time Low High Data Resiliency Low High Application Resiliency Low High Degree of Distributed Access/Synchronization Often Never Scheduled Maintenance Frequency Low High Performance/Scalability Low High Cost of Downtime ($$ lost/hr) Low High Cost of the High Availability Solution ($$) Copyright 2009 – Database Architechs www.dbarchitechs.com
  13. 13. Development Methodology “With High Availability built in” Assessment Assessment (scope) (scope) 3. Code & Test - Code Development/Unit Testing - Fully integrate the HA solution with the application 0. Assessment Requirements Requirements 4. System Test & Acceptance - Project Planning - Full system Test/User Acceptance - Project Sizing - Full HA Test/Validation/Acceptance - Deliverables Identified (SOW) - Schedules/milestones Design Design 5. Implementation - Production Build/Implementation - High-Level Requirements (scope) - Production HA build/monitoring begins - Estimate HA Primary Variables (gauges) 1. Requirements Code & Test Code & Test - Detail Requirements (process/data/technology) - Early Prototyping (optional) - Detailed HA Primary Variables System Test & System Test & - Detailed Service Level Agreements/Rqmts Acceptance - Detailed Disaster Recovery requirements Acceptance 2. Design Implementation Implementation - Detail Design (data/process/technology) - Choose and design the matching HA solution for the application Copyright 2009 – Database Architechs www.dbarchitechs.com
  14. 14. Spiral/Rapid Methodology Iterative approach 0. Initial assessment - Project Planning 7. Implementation - Project Sizing - Production Build/Implementation - Deliverables Identified (SOW) - Production HA build/monitoring begins - Schedules/milestones - High-Level Functions (scope) Transition Inception -Estimate HA Primary Variables (gauges) 3. Requirements 6. System Test & Acceptance - Detail Requirements - Full system Test/User (process/data/technology) Acceptance - Detail HA Primary Variables -Full HA Test/Validation - Detailed SLA/Rqmts /Acceptance - Detailed Disaster Recovery requirements 5. Code & Test 1. High-level Rqmts/Prototyping - Code Development/Unit Testing - High-level requirements -Fully integrate the HA solution (process/data/technology) with the application - High-level HA Primary Variables Construction Elaboration/Prototype 2. Early Code & Test 4. Design - Early code and testing of apps/DI - Detail Designs (process/data/technology) (process/data/technology) Copyright 2009 – Database Architechs - Choose and design the matching HA solution - Prototyping of HA options www.dbarchitechs.com for the application (verified via prototypes)
  15. 15. Valid High Availability Options Disk Other Cluster Data SQL DB Log Methods HW Services Replication Clustering Mirroring Shipping Disk Methods Other HW Cluster Services Data Replication SQL Clustering DB Mirroring Log Shipping Copyright 2009 – Database Architechs www.dbarchitechs.com
  16. 16. MSCS Cluster Services C: Local Binaries Windows 2003 Node A Enterprise Edition Cluster Group Resources D: Shared SCSI Disk Q: Quorum Windows 2003 Node B Enterprise Edition C: Copyright 2009 – Database Architechs Local www.dbarchitechs.com Binaries
  17. 17. SQL SQL Clustering Connections COLTST1 C: Local Binaries Windows 2003 Enterprise Edition Cluster Group Resources SQL Server 2008 (physical) E: MS DTC Master DB SQL Server 2008 SCSI TempDB (Virtual SQL Server) Appl 1 DB VSQLDBARCHVSQLSRV1 Q: Quorum Disk SQL Server 2008 (physical) SQL Agent Windows 2003 COLTST2 Enterprise Edition C: Copyright 2009 – Database Architechs Local www.dbarchitechs.com Binaries
  18. 18. Data Replication Can be used as a Warm Standby and/or for Reporting needs “Primary” SQL Server 2008 “Replicate” SQL Server 2008 Publication Subscription Adventure Server Server Works AdventureWorks Distribution Server distribution “Replicate” SQL Server 2008 SQL Server 2008 Subscription Server Central Publisher/ AdventureWorks Remote Distributor Replication model Copyright 2009 – Database Architechs www.dbarchitechs.com
  19. 19. Database Mirroring Client Client Client Client Network A SQL Server 2008 SQL Server 2008 Database Mirror Server MirroringAdventure Principal Works DB D Adventure D Server B Works DB translog translog C SQL Server 2008 Witness MSDB DB Server
  20. 20. Database Mirroring with DB Snapshots SQL Server 2008 SQL Server 2008 Mirror Server 20FIG34 AdventureWorks AdventureWorks Principal DB DB Server translog translog Database Snapshot SQL Server 2008 rk rk s oo Witness er tw tw Us MSDB DB Ne Server Ne ng rti po Re
  21. 21. Log Shipping “Source” SQL Server 2008 “Destination” SQL Server 2008 TxnLog Primary CallOne DB backups Secondary Server Server translog CallOne DB BackupCallOne_tlog_200405141120.TRN Last log shipped Delay Answer LogShareCallOne_tlog_200405141120.TRN TxnLog TxnLog Copies Restores “Monitor” SQL Server 2008 Delay between logs loaded Delay Answer Monitor MSDB DB Server Copyright 2009 – Database Architechs www.dbarchitechs.com
  22. 22. RAID Disk I/O Summary RAID Level Fault Tolerance Logical Physical I/Os Logical Physical Reads per Writes I/Os per Write Read RAID 0 None 1 1 1 1 RAID 1 or 10 Best 1 1 1 2 writes (Optimal for OLTP) RAID 5 Moderate 1 1 1 2 reads + 2 writes (Optimal for mostly (that’s 4 per write!) READ ONLY systems) NOTE: Several RAID vendors are now showing RAID 5 and RAID 10 performance almost equivalent now via Cache/Buffer advancements on their RAID controllers Copyright 2009 – Database Architechs www.dbarchitechs.com
  23. 23. Fault Tolerance and SQL DB Files Description Fault Tolerance Quorum Drive The quorum drive used with MSCS should be RAID 1 or isolated to a drive by itself (very often mirrored RAID 10 as well for maximum availability) SQL Server For OLTP (online transaction processing) systems, RAID 10 Database the database data/index files should be placed files (OLTP) on a RAID 10 disk system. SQL Server For DSS (Decision Support Systems) systems that RAID 5 Database are primarily READ ONLY, the database files (DSS) data/index files should be placed on a RAID 5 disk system. Temp DB Highly volatile disk I/O (when not able to do all it’s RAID 10 work in cache) SQL Server The SQL transaction log files should be on their own RAID 10 Transaction mirrored volume for both performance and Or Log files database protection. (for DSS systems, this RAID 1 could be RAID 5 also). Copyright 2009 – Database Architechs www.dbarchitechs.com
  24. 24. Example DB data files configuration E: RAID 5 Master DB log DSS - DB F: (read only) TempDB RAID 10 log G: OLTP X - DB log OLTP Y - DB H: RAID 1 or RAID 10 Q: Quorum Copyright 2009 – Database Architechs www.dbarchitechs.com
  25. 25. Decision Tree approach Condition/Question Case A Case B Case C Case D . . . Case n Action Action Action Action . . . Action V W X Y Z Disk Other Cluster Data SQL Database Log Distributed Methods HW Services Replication Clustering Mirroring Shipping Transactions Copyright 2009 – Database Architechs www.dbarchitechs.com Database Snapshots
  26. 26. Decision-Tree Path Traversal SQL Clustering Database Cluster Snapshots Services 1a2c3 1a2d3 1a2e3 1a2b3 Database b c d Mirroring a 1a2 e 1a2a3 HA a b 1b2 1e2 e 1 c Not Needed d 1c2 Log 1d2 Shipping HW/Disk Redundancy Data Distributed Replication Transactions Copyright 2009 – Database Architechs www.dbarchitechs.com
  27. 27. Decision-Tree: ASP Questions 1-3 1 What % of availability must your application have? A% <= 70% 70% < A% < =83% 83 < A% < =95% 95% < A% < =99.5% A%> 99.5% Marginal Acceptable Standard High Extreme Availability Availability Availability Availability Availability 2 How much tolerance of downtime by end-users? Very High High Medium Low Very Low Not Low Standard High Extremely Critical Criticality Criticality Criticality Critical 3 What is the per hour cost of downtime for this application? $C<= $3K $3K < $C < =$7K $7K < $C < =$12K $12K < $C < =$20K $C > $20K Very Low Low Moderate High Very High Cost Cost Cost Cost Cost Copyright 2009 – Database Architechs www.dbarchitechs.com
  28. 28. Decision-Tree: ASP Questions 4-6 4 How long does it take to get the application back online? Very Long Long Average Short Very Short Marginal Acceptable Standard Fast Extreme Recoverability Recoverability Recoverability Recoverability Recoverability 5 How much of the application is distributed? None A Little Medium A Lot All Non- Low Moderately High Extremely Distributed Distribution Distributed Distribution Distributed 6 How much data inconsistency can be tolerated? Very Little A Little Medium A Lot Very Much Very High High Moderate Low Minimal Consistency Consistency Consistency Consistency Consistency Copyright 2009 – Database Architechs www.dbarchitechs.com
  29. 29. Decision-Tree: ASP Questions 7-9 7 How often is scheduled maintenance required? Very Often Often Average Not Often Rarely Very High High Reasonable Low Minimal Downtime Downtime Downtime Downtime Downtime 8 How important is high performance and scalability? Not Very Somewhat Moderately Very Much Extremely Very low Low Reasonable High Extreme Performance Performance Performance Performance Performance 9 How important is the application connection to the end-user? Not Very Somewhat Moderately Very Much Extremely Connection Connection Connection Not Establish new Re-established Retry process Fail-over Needed Connection easily Copyright 2009 – Database Architechs www.dbarchitechs.com
  30. 30. Decision-Tree: ASP Question 10 10 What is the estimated cost of the HA Solution (budget)? C$ < $10K $10K <= C$ < $100K $100K <= C$ < $250K $250K <= C$ < $500K C$ >= $500K Very Low Low Moderate High Extreme Cost Cost Cost Cost Cost 1. 1e Extreme Availability goal 2. 1e+2d Very low tolerance of downtime 3. 1e+2d+3e $15k/hr cost of downtime (High Cost) 4. 1e+2d+3e+4c Average recovery time 5. 1e+2d+3e+4c+5a No distributed components or synchronization 6. 1e+2d+3e+4c+5a+6b A little data inconsistency can be tolerated 7. 1e+2d+3e+4c+5a+6b+7c Average amount of scheduled downtime 8. 1e+2d+3e+4c+5a+6b+7c+8d Performance is very much important 9. 1e+2d+3e+4c+5a+6b+7c+8d+9b Connection can be re-established 10. 1e+2d+3e+4c+5a+6b+7c+8d+9b+10c Moderate HA Cost/Good budget Best fitting HA Solution (together) Disk Other Cluster SQL Copyright 2009 – Database Architechs Methods HW Services www.dbarchitechs.com Clustering
  31. 31. Basic “one-two” Punch approach 1 Build the proper foundation first Hardware/Network Disk Backups Vendor Training, QA, Software Redundancy DB Backups SLA’s & Standards Upgrades Then, build within the appropriate HA solution 2 that your application requires Disk Other Cluster Data SQL Database Log Distributed Methods HW Services Replication Clustering Mirroring Shipping Transactions Database Snapshots Copyright 2009 – Database Architechs www.dbarchitechs.com
  32. 32. ASP – Scenario #1 with SQL Clustering ASPProd1 C: Local Binaries Windows 2003 MSCS Enterprise Edition Cluster Group Resources JRUN/WebServices/IIS SQL Server 2005 (physical) Master DB E: Network TempDB SQL Server 2005 SCSI F: (Virtual SQL Server) ASQLASPSERV1 HOE DB G: MS DTC Q: Quorum SQL Server 2005 (physical) SQL Agent Disk Windows 2003 Enterprise Edition MSCS C: ASPProd2 Active/Passive Copyright 2009 – Database Architechs Local Binaries Configuration www.dbarchitechs.com
  33. 33. Log Shipping “Source” SQL Server 2000 “Destination” SQL Server 2000 TxnLog Primary CallOne DB backups Secondary Server Server translog CallOne DB BackupCallOne_tlog_200405141120.TRN Last log shipped Delay Answer LogShareCallOne_tlog_200405141120.TRN TxnLog TxnLog Copies Restores “Monitor” SQL Server 2000 Delay between logs loaded Delay Answer Monitor MSDB DB Server Copyright 2009 – Database Architechs www.dbarchitechs.com
  34. 34. North America (Reporting & “warm/hot” spare) SQL Server 2000 Headquarters (Santa Clara) Subscription SQL Server 2000 Server Live REPL MktgDB Publication solution Server MktgDB Europe (Reporting) SQL Server 2000 Subscription Distribution Server Server distribution MktgDB SQL Server 2000 Far East (Reporting) SQL Server 2000 Central Publisher/ Subscription Remote Distributor Server Replication model MktgDB Copyright 2009 – Database Architechs www.dbarchitechs.com
  35. 35. SQL Server 2000 Central Publisher SQL Server 2000 Subscription (default option) Subscription Server Server Northwind SQL Server 2000 Northwind Publication Server Northwind Distribution Server distribution Oracle SQL Server 7.0 Subscription Subscription Server Server Northwind Northwind Copyright 2009 – Database Architechs www.dbarchitechs.com
  36. 36. Central Publisher SQL Server 2000 SQL Server 2000 Subscription Remote Distributor Subscription Server Server Northwind SQL Server 2000 Northwind Publication Server Northwind Distribution Server distribution SQL Server 2000 Oracle SQL Server 7.0 Subscription Subscription Server Server Northwind Northwind Copyright 2009 – Database Architechs www.dbarchitechs.com
  37. 37. Data Access Latency Autonomy Distributing Data Sites (locations) Frequency Network Machines Owner Other REPLICATION Read Only Each site only Central Publisher short high many high fast/ 1 1 OLTP needs regional Transactional repl Reporting stable server/site Database Mirroring site data filter by region Read Only Each site only Central Publisher fast/ 1 Snapshot repl Reporting long high many low 1 OLTP needs regional stable server/site Database Mirroring site data filter by region Read Mostly Regional updates Central Publisher fast/ 1 Transactional repl A few updates short high < 10 medium 1 OLTP on one table stable server/site site Updating Subs Read Mostly Regional update Central Publisher slow/ 1 All Merge repl A few updates medium high < 10 medium unreliab server/site update all tables Read equal Regional update Peer-to-Peer fast/ 1 All Transactional Equal updates short high < 10 medium all tables stable server/site update repl Inserts 1 Each site only Central Subscriber short high many high fast/ 1 Transactional repl (new orders) report needs regional stable server/site data site Central Publisher Hot/Warm Very fast/ 1 Fail-over Remote Distributor high <2 high 1 OLTP Spare short stable server/site Transactional repl site Database Mirroring
  38. 38. Foundation, Foundation, Foundation Piecing it together Hardware/Network Disk Backups Vendor Training, QA, Software Redundancy DB Backups SLA’s & Standards Upgrades Network Application Middleware Database HARDWARE Operating Network Components System Servers Disk Systems ck Memory Sta ystem S Copyright 2009 – Database Architechs www.dbarchitechs.com
  39. 39. ROI Calculati on Copyright 2009 – Database Architechs www.dbarchitechs.com
  40. 40. Database Mirroring Transparent Client Redirect Network A SQL Server 2008 SQL Server 2008 Mirror Server Principal Applx DB D Applx DB D Server B translog translog C “Copy-on-Write” technology SQL Server 2008 Witness MSDB DB Server Copyright 2009 – Database Architechs www.dbarchitechs.com
  41. 41. 20FIG30 SQL Server 2005 Database Mirroring
  42. 42. 20FIG31 SQL Server 2008 Database Mirroring
  43. 43. 16 43 Copyright 2009 all rights reserved
  44. 44. Database Mirroring with DB Snapshot SQL Server 2005 SQL Server 2005 Mirror Server Principal Applx DB Applx DB Server translog translog Database Snapshot SQL Server 2005 rk rk s oo Witness er tw tw Us MSDB DB Ne Server Ne ng rti po Re Copyright 2009 – Database Architechs www.dbarchitechs.com
  45. 45. Snapshot Source Data Users Pages SELECT …..data……. FROM AdventureWorks SNAPSHOT 04 SQL Server 2008 SQL Server Snapshot AdventureWorks AdventureWorks DB DB System Catalog Sparse of changed pages File Pages
  46. 46. Instance: SQL2008xyz PH Topology With Snapshots Endpoint Name: “endpoint4mirroring” Role: PARTNER Critical Report Network Network Users SQL Server 2008 Principal Instance: SQL2008zzz Endpoint Name: “endpoint4mirroring” Server Role: PARTNER SQL Server 2008 OLTP Application Active Mirror Server Clustered Replication Adventure Adventure Works DB Works DB translog translog Database Passive Snapshot PH Topology Network Network Principal Server SQL Server 2008 Less Critical Reporting Users
  47. 47. Publisher The Combo Pack SQL Server 2008 SQL Server 2008 Principal Mirror SQL Server 2008 Server Server Subscriber Distributor SQL Server 2008 SQL Server 2008 Principal Mirror Server Server SQL Server 2008 SQL Server 2008 Witness Server Subscriber Copyright 2009 – Database Architechs www.dbarchitechs.com
  48. 48. Restart Stage Rolled Forward time Transactions SQL Server SQL Server 2000 2005/2008 SQL SQL Server Server Transactions Rolled Back SQL Server 2005/2008 database is available SQL Server 2000 database is available complete Restart DB Availability Improvement ! Copyright 2009 – Database Architechs www.dbarchitechs.com
  49. 49. Performance and Tuning counts in HA SQL SHOT – MS SQL Server
  50. 50. Questions Is there any time left???? Copyright 2009 – Database Architechs www.dbarchitechs.com
  51. 51. SQL Server Resources Stop! Copyright 2009 – Database Architechs www.dbarchitechs.com
  52. 52. Fail-Over via Move Group ANSWER to question #1 Copyright 2009 – Database Architechs www.dbarchitechs.com
  53. 53. Distributed Transactions “Primary Location” SQL Server 2000 Try primary first Reads Northwind 1 If no ta va ila ble , try “Secondary Location” MS DTC sec SQL Server 2000 on Updates da ry Northwind 2 Must succeed together, or be both rolled back (two-phase commit) Copyright 2009 – Database Architechs www.dbarchitechs.com

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