Download - Assaf Fraenkel Principal Consultant Microsoft Consulting Services High Availability with SQL 2005 זמינות יתרה והמשך פעילות עסקית

Assaf Fraenkel

Principal Consultant

Microsoft Consulting Services

High Availability with SQL 2005 זמינות יתרה והמשך פעילות עסקית

Availability “Stack”Availability “Stack”

Majority of downtime is Majority of downtime is ascribed to operatorsascribed to operatorsApplication Software can Application Software can have dramatic impact on have dramatic impact on fault tolerancefault toleranceSystem Software can System Software can help at all levelshelp at all levelsHardware is very reliable Hardware is very reliable at this pointat this pointHardwareHardware

SystemSystemSoftwareSoftware

ApplicationApplicationSoftwareSoftware

OperatorsOperators

Barriers To AvailabilityBarriers To Availability

SS 2005 gives you greatly SS 2005 gives you greatly improved tools to overcome these improved tools to overcome these barriers barriers

Database Server Failure or DisasterDatabase Server Failure or DisasterUser or Application ErrorUser or Application ErrorData Access Concurrency LimitationsData Access Concurrency LimitationsDatabase Maintenance and Database Maintenance and OperationsOperationsUpgradesUpgrades

Only some are addressable by DBMS technologyOnly some are addressable by DBMS technologyBe sure to consider people, planning, and proceduresBe sure to consider people, planning, and procedures

Availability SolutionsAvailability SolutionsHow Do You Compare the Alternatives How Do You Compare the Alternatives (1/2)(1/2)

Time to Fail OverTime to Fail OverAutomatic or Manual DetectionAutomatic or Manual DetectionAutomatic or Manual FailoverAutomatic or Manual FailoverNumber of Failures it can surviveNumber of Failures it can surviveData Currency / LossData Currency / Loss

Availability SolutionsAvailability SolutionsHow Do You Compare the Alternatives How Do You Compare the Alternatives (2/2)(2/2)

Granularity of Data: Instance, Database, Table, Granularity of Data: Instance, Database, Table, RowRowCost of redundant system(s), additional Cost of redundant system(s), additional hardware, additional managementhardware, additional managementComplexityComplexityData ConsistencyData ConsistencyTransparency to clientsTransparency to clients

Availability Technologies in Availability Technologies in SQL Server 2005SQL Server 2005

Availability Technologies in Availability Technologies in SQL Server 2005SQL Server 2005

Basic:Basic: No failover and a potential data loss No failover and a potential data lossBackup / restoreBackup / restoreDetach / copy / attachDetach / copy / attach

Better:Better: Manual failover - potential data loss Manual failover - potential data lossPeer-to-Peer ReplicationPeer-to-Peer ReplicationLog ShippingLog ShippingDatabase Mirroring - high performance modeDatabase Mirroring - high performance mode

Best:Best: Automatic failover - zero data loss Automatic failover - zero data lossDatabase Mirroring - high availability modeDatabase Mirroring - high availability modeFailover ClusteringFailover Clustering

Backup / RestoreBackup / Restore

Detach / Copy / AttachDetach / Copy / Attach

Cold Standby SolutionsCold Standby SolutionsBackup / Restore and Backup / Restore and Detach / Copy / AttachDetach / Copy / Attach


Both ProvideBoth ProvideManual detectionManual detection and failover and failoverPotential for some work lossPotential for some work lossWhole-database scopeWhole-database scopeStandard serversStandard serversLimited reporting on standbyLimited reporting on standbyDuplicate copy of databaseDuplicate copy of databaseClient must know where to re-Client must know where to re-connectconnectSlowest failover – Most downtimeSlowest failover – Most downtime



Backup / Restore Backup / Restore What’s New in SQL Server 2005What’s New in SQL Server 2005

Fine-Grained Fine-Grained Online RepairOnline RepairOnline Restore – Database remains online; Online Restore – Database remains online; Only Only data being restored is offlinedata being restored is offlinePiecemeal Restore – Online restore of filegroups Piecemeal Restore – Online restore of filegroups by priorityby priorityPage-level RestorePage-level Restore – Can restore individual – Can restore individual pages to repair errors found by page checksum pages to repair errors found by page checksum or torn pagesor torn pages

Instant File Initialization – Instant File Initialization – Skips file zeroingSkips file zeroing, , fast DB create / restorefast DB create / restoreData backups do not block log backupsData backups do not block log backupsRestore read-only filegroups without Restore read-only filegroups without applying logsapplying logsBackup / Restore Backup / Restore includes FullTextincludes FullText data data

Warm Standby SolutionsWarm Standby SolutionsReplication and Log ShippingReplication and Log Shipping

ReplicationReplication

Log ShippingLog Shipping

Warm Standby SolutionsWarm Standby SolutionsReplicationReplication

Multiple copies and Manual Multiple copies and Manual failoverfailoverPrimarily used where Primarily used where availability is required in availability is required in conjunction with scale out of conjunction with scale out of read activityread activityFailover possible; a custom Failover possible; a custom solutionsolutionNot limited to entire Not limited to entire database; database; Can define subset Can define subset of source database or tablesof source database or tablesCopy of database is Copy of database is continuously accessible for continuously accessible for read activityread activityLatency between source and Latency between source and copy can be as low as copy can be as low as secondsseconds


Peer-to-Peer Peer-to-Peer Transactional Transactional ReplicationReplicationAll participants are peersAll participants are peers

Schema is identical on all sitesSchema is identical on all sitesPublish the updates made on ‘their’ dataPublish the updates made on ‘their’ dataSubscribe to others to pick up their changesSubscribe to others to pick up their changesNo hierarchy as in ‘normal’ transactional No hierarchy as in ‘normal’ transactional replicationreplication

A given set of data can be updated at only one A given set of data can be updated at only one site at a timesite at a time

Data ‘ownership’ is purely logical; doesn’t prevent Data ‘ownership’ is purely logical; doesn’t prevent conflictsconflictsSQL Server prevents a change from round-trippingSQL Server prevents a change from round-tripping

Enables load-balancing and high availabilityEnables load-balancing and high availabilityWarm/hot standby - Small possibility of data Warm/hot standby - Small possibility of data lossloss

Peer-to-Peer Transactional Peer-to-Peer Transactional ReplicationReplication

Warm Standby SolutionsWarm Standby SolutionsLog ShippingLog Shipping

Multiple copies and Manual Multiple copies and Manual failoverfailoverBasic idea: Backup, Copy & Basic idea: Backup, Copy & Restore Log will always be Restore Log will always be supportedsupported

But no more investment in the But no more investment in the scriptsscripts

Database scopeDatabase scopeDatabase accessible but read-Database accessible but read-onlyonlyUsers must exit for next log to Users must exit for next log to be appliedbe appliedData backups no longer block Data backups no longer block log backupslog backups

Log ShippingLog Shipping

Hot Standby Failover SolutionsHot Standby Failover SolutionsFailover Clustering and Database MirroringFailover Clustering and Database Mirroring

Both ProvideBoth ProvideAutomatic detectionAutomatic detectionAutomatic, fast failoverAutomatic, fast failoverManual failoverManual failoverTransparent client Transparent client redirectredirectZero work lossZero work loss Database MirroringDatabase MirroringFailover ClusterFailover Cluster

Zero work loss, Zero work loss, zero impact on zero impact on throughputthroughputInstanceInstance Failover –instance fails as a Failover –instance fails as a unitunitSingleSingle copy of instance databases copy of instance databases Standby is Standby is not available for reportingnot available for reporting, , queries, etc.queries, etc.

May support other instancesMay support other instances

Failover Clustering Failover Clustering Microsoft Server ClusterMicrosoft Server Cluster

Failover ClusterFailover Cluster

* Inst1* Inst1

Failover Clustering Failover Clustering SQL Server 2005SQL Server 2005

More nodesMore nodesMatch operating system limitsMatch operating system limitsSupported scenarios: Multiple Active Supported scenarios: Multiple Active Instances, N+1, N+IInstances, N+1, N+ITwo-node Failover Clustering is available Two-node Failover Clustering is available in SQL Server 2005 Standard Editionin SQL Server 2005 Standard Edition

Unattended setupUnattended setupSupport for mounted volumes (Mount Support for mounted volumes (Mount Points)Points)All SQL Server data services participateAll SQL Server data services participate

Database Engine, SQL Server Agent, Database Engine, SQL Server Agent, Full-Text SearchFull-Text SearchAnalysis Services supports Analysis Services supports multiple multiple instancesinstances

N+1: N Active, 1 Inactive N+1: N Active, 1 Inactive InstancesInstances

* Inst1* Inst1

Inst2 *Inst2 *

Multiple Active InstancesMultiple Active Instances N+I: N Active, I Inactive N+I: N Active, I Inactive InstancesInstances

Database MirroringDatabase MirroringNew for SQL Server 2005New for SQL Server 2005Database MirroringDatabase MirroringNew for SQL Server 2005New for SQL Server 2005

Hot StandbyHot StandbyDatabase FailoverDatabase Failover

Very fast failoverVery fast failoverLess than five seconds in Less than five seconds in mostmost cases cases

Zero data lossZero data loss

Automatic or manual failoverAutomatic or manual failoverAutomatic re-sync after failoverAutomatic re-sync after failover

Automatic, transparent client redirectAutomatic, transparent client redirect

Database MirroringDatabase Mirroring


Fault Tolerant Virtual DatabaseFault Tolerant Virtual Database

PrincipalPrincipal

ClientsClients

WitnessWitness

MirrorMirror

Witness and QuorumWitness and Quorum

SoleSole purpose of the Witness is purpose of the Witness is to provide to provide automaticautomatic failover failoverTo survive the loss of To survive the loss of oneone server you must server you must have at least have at least threethreeWitness is an instance of SQL Server 2005Witness is an instance of SQL Server 2005

Perhaps even SQL Server Express on WinXP Perhaps even SQL Server Express on WinXP

Consumes very little resourcesConsumes very little resourcesCan be witness for multiple sessionsCan be witness for multiple sessions

WitnessWitness

Database Mirroring Database Mirroring How it worksHow it works

MirrorMirrorPrincipalPrincipal

WitnessWitness

Log

Application

SQL Server SQL Server

2

2

4

51

Data DataLog

3>2 >3

Mirror is always Mirror is always redoing – redoing – it remains currentit remains currentCommit

Safety / PerformanceSafety / PerformanceThere is a trade-off between There is a trade-off between performance and safetyperformance and safetyDatabase Mirroring has two safety Database Mirroring has two safety levelslevels

FULL – commit when logged on MirrorFULL – commit when logged on MirrorAllows automatic failoverAllows automatic failoverNo data lossNo data loss

OFF – commit when logged on PrincipalOFF – commit when logged on PrincipalSystem does its best to keep upSystem does its best to keep upPrevents failover; to make mirror availablePrevents failover; to make mirror available

Must ‘force’ serviceMust ‘force’ serviceOr terminate Database Mirroring sessionOr terminate Database Mirroring session

Database MirroringDatabase MirroringHigh Availability ModeHigh Availability Mode

PrincipalPrincipal

ClientsClients

WitnessWitness

MirrorMirror

XX

High Protection ModeHigh Protection ModeHigh Performance ModeHigh Performance Mode

Transparent Client RedirectTransparent Client Redirect

No changes to application codeNo changes to application codeClient automatically redirected if Client automatically redirected if session is droppedsession is dropped

Client library is aware of Principal and Client library is aware of Principal and Mirror serversMirror serversUpon initial connect to Principal, library Upon initial connect to Principal, library caches Mirror namecaches Mirror nameWhen client attempts to reconnectWhen client attempts to reconnect

If Principal is available, connectsIf Principal is available, connectsIf not, client library automatically redirects If not, client library automatically redirects connection to Mirrorconnection to Mirror


Impact to transaction Impact to transaction throughputthroughput

Depending on environment Depending on environment Depending on workloadDepending on workloadZero to minimalZero to minimal

HardwareHardwareWorks with standard Works with standard computers, storage, computers, storage, and networksand networksNo shared storage components, virtually No shared storage components, virtually no distance limitationsno distance limitationsMy Tips: 1GB Network, Disk for the My Tips: 1GB Network, Disk for the LogLog


Geographically-Dispersed Geographically-Dispersed Clusters and Clusters and Storage-level ReplicationStorage-level Replication

Solutions from many Microsoft partners Solutions from many Microsoft partners replicate the local I/Os on a remote systemreplicate the local I/Os on a remote system

Hardware and software methodsHardware and software methodsSynchronous and asynchronous solutionsSynchronous and asynchronous solutions

Solutions Solutions mustmust meet Core I/O Requirements meet Core I/O RequirementsMany solutions use MSCS to provide Many solutions use MSCS to provide automatic failoverautomatic failoverOther solutions are primarily to duplicate Other solutions are primarily to duplicate the data at a remote site, often with an the data at a remote site, often with an independent SQL Serverindependent SQL Server

Similar to Log Shipping or Detach / AttachSimilar to Log Shipping or Detach / Attach

Geographical Geographical Failover ClusterFailover Cluster

Complementary Complementary TechnologiesTechnologiesTechnologies can be CombinedTechnologies can be Combined

Maximize availability forMaximize availability forScale outScale out

Offload primary data platformOffload primary data platform

Heavy reportingHeavy reportingMobile/disconnected usersMobile/disconnected usersAutonomous business units that share Autonomous business units that share datadata

Maximize availability of critical Maximize availability of critical systemssystems

Designed for failoverDesigned for failoverFast, automaticFast, automatic

Zero data lossZero data lossTransactionally currentTransactionally currentMasks planned and unplanned Masks planned and unplanned downtimedowntime


Failover SolutionsFailover Solutions

ExampleExampleFault-Tolerant Publisher and Fault-Tolerant Publisher and

Distributor Distributor SubscribersSubscribers

Complementary TechnologiesComplementary TechnologiesFailover Solution + ReplicationFailover Solution + Replication

DistributorDistributor

PublisherPublisher

Combining HA Combining HA TechnologiesTechnologies

Principal Server can be a Failover ClusterPrincipal Server can be a Failover ClusterFailover to mirror will occur before failover Failover to mirror will occur before failover within the clusterwithin the cluster

So Principal will come back up as the MirrorSo Principal will come back up as the Mirror

Mirror can be a Failover Cluster as wellMirror can be a Failover Cluster as well

PrincipalPrincipal MirrorMirror

Failover ClusterFailover Cluster Failover ClusterFailover Cluster

Barriers To AvailabilityBarriers To AvailabilityAs addressed in SQL Server 2005As addressed in SQL Server 2005

Database Server Failure or DisasterDatabase Server Failure or Disaster----------------------------------------------------------------------------------------------------------------

--------Application or User ErrorApplication or User Error

Database SnapshotsDatabase Snapshots

Data Access Concurrency LimitationsData Access Concurrency LimitationsDatabase Maintenance and Database Maintenance and OperationsOperationsUpgradesUpgrades

Barriers to AvailabilityBarriers to Availability

This job would be great

if it weren’t for……the users…the staff

…us

PeopleI’m going I’m going to modify to modify this data…this data…

right…right…

herhere!e!

Database SnapshotDatabase SnapshotNew in SQL Server 2005New in SQL Server 2005

Database Snapshots allow recovery Database Snapshots allow recovery from user errors by allowing the from user errors by allowing the database to go back in timedatabase to go back in timeWorks withWorks with

Single serverSingle serverDatabase MirroringDatabase MirroringFailover ClusterFailover Cluster

Does Does notnot work with Log Shipping work with Log Shipping secondarysecondary

Database Snapshot Database Snapshot How it really worksHow it really works

mydbSnap – Read-Only Database SnapshotmydbSnap – Read-Only Database SnapshotUSE mydbSnapUSE mydbSnapSELECT SELECT (pages 4, 6, 9, 10, 14)(pages 4, 6, 9, 10, 14)

11

PagePage

22 33 44 55 66 77 88 99 1010 1111 1212 1313 1414 1515 1616

CREATE DATABASE mydbSnap AS SNAPSHOT OF mydbCREATE DATABASE mydbSnap AS SNAPSHOT OF mydb

mydb – Databasemydb – Database

USE mydbUSE mydbUPDATEUPDATE (pages 4, 9, 10) (pages 4, 9, 10)

44 99 101011 22 33 44 55 66 77 88 99 1010 1111 1212 1313 1414 1515 1616

Database SnapshotDatabase SnapshotTechnologyTechnology

Extremely space efficientExtremely space efficientDoes Does notnot require a complete copy of require a complete copy of the datathe data

Shares unchanged pages of the databaseShares unchanged pages of the databaseRequires extra storage only for Requires extra storage only for changed pageschanged pages

Uses a “copy-on-write” mechanismUses a “copy-on-write” mechanismDatabase Snapshot may affect Database Snapshot may affect performance on the base databaseperformance on the base database

Reporting on a MirrorReporting on a MirrorUse Database Snapshots on MirrorUse Database Snapshots on Mirror

MirrorMirror

PrincipalPrincipal

Reporting Reporting ClientsClients


OLTP ClientsOLTP Clients

Snapshot1Snapshot1at 1PMat 1PM

WitnessWitness

Snapshot2Snapshot2at 2PMat 2PM


Database Server Failure or DisasterDatabase Server Failure or DisasterApplication or User ErrorApplication or User ErrorData Access Concurrency LimitationsData Access Concurrency Limitations

Snapshot IsolationSnapshot IsolationOnline Index OperationsOnline Index Operations

Database Maintenance and Database Maintenance and OperationsOperationsUpgradesUpgrades

Online Index OperationsOnline Index Operations

Online Index Operations allow concurrent Online Index Operations allow concurrent modification of the underlying table or modification of the underlying table or indexindex

Updates, Inserts, DeletesUpdates, Inserts, Deletes

Online Index MaintenanceOnline Index MaintenanceCreate, Rebuild, DropCreate, Rebuild, DropIndex-based constraints (PrimaryKey, Unique)Index-based constraints (PrimaryKey, Unique)

Data definition language (DDL) is simpleData definition language (DDL) is simpleOnline/Offline are both supported Online/Offline are both supported Updates incur some additional cost during Updates incur some additional cost during an online index operationan online index operation

Maintains old and new indexesMaintains old and new indexes


Database Server Failure or DisasterDatabase Server Failure or DisasterApplication or User ErrorApplication or User ErrorData Access Concurrency LimitationsData Access Concurrency LimitationsDatabase Maintenance and Database Maintenance and OperationsOperationsUpgradesUpgrades

Fast RecoveryFast RecoveryRestart of a DatabaseRestart of a Database

SQL Server 2000SQL Server 2000Database is available after Undo Database is available after Undo completescompletes

SQL Server 2005SQL Server 2005Database is available when Undo Database is available when Undo beginsbegins

UndoUndoRedoRedo

AvailableAvailable

UndoUndoRedoRedo

AvailableAvailable

TimeTime

Database Maintenance & Database Maintenance & OperationsOperations

Partial AvailabilityPartial AvailabilityDatabase is available if primary filegroup Database is available if primary filegroup is availableis available

Online RestoreOnline RestoreRestore while database remains availableRestore while database remains availableWorks with all recovery modelsWorks with all recovery models

Backup and RestoreBackup and RestoreData backups don’t block log backupsData backups don’t block log backupsFull-Text Catalog is backed up and Full-Text Catalog is backed up and restored as part of the databaserestored as part of the database

More Operational More Operational Improvements… Improvements…

Dedicated Administration ConnectionDedicated Administration ConnectionProvides DBA access to server regardless of loadProvides DBA access to server regardless of loadNo server restart to kill a runaway sessionNo server restart to kill a runaway session

More configuration is dynamicMore configuration is dynamicNo server restart for CPU affinity, AWENo server restart for CPU affinity, AWEAddress Windowing Extensions (AWE)Address Windowing Extensions (AWE)

Changes to physical size don’t requireChanges to physical size don’t require downtime downtimeDynamically configurable (Min / Max)Dynamically configurable (Min / Max)Dynamically adjusts to “hot-add” memoryDynamically adjusts to “hot-add” memory

AWE is available in Standard Edition (Win2003)AWE is available in Standard Edition (Win2003)

Instant file initializationInstant file initializationWith appropriate security, can bypass zeroingWith appropriate security, can bypass zeroingFor create database, add file, file grow, restoreFor create database, add file, file grow, restore


Database Server Failure or DisasterDatabase Server Failure or DisasterApplication or User ErrorApplication or User ErrorData Access Concurrency LimitationsData Access Concurrency LimitationsDatabase Maintenance and Database Maintenance and OperationsOperationsUpgradesUpgrades

Upgrade EnhancementsUpgrade EnhancementsSoftware UpgradeSoftware Upgrade

Re-architected – Re-architected – greatly reduces down timegreatly reduces down timeSide-by-side installationSide-by-side installationResource database is pre-builtResource database is pre-built

No maintenance is needed; new is substituted for old No maintenance is needed; new is substituted for old oneoneDBA can ignore the mssqlsystemresource.mdf and ldfDBA can ignore the mssqlsystemresource.mdf and ldf

PhasedPhasedEngine and Databases (< 3 minutes)Engine and Databases (< 3 minutes)Other components complete upgrade online after Other components complete upgrade online after databases are available (Replication, Workbench, etc.)databases are available (Replication, Workbench, etc.)

Hardware UpgradeHardware UpgradeHot-add memoryHot-add memory supported without server restart supported without server restartDatabase Mirroring minimizes downtimes for Database Mirroring minimizes downtimes for other hardware upgrades, excluding diskother hardware upgrades, excluding disk

SQL Server 2005SQL Server 2005Capabilities by EditionCapabilities by Edition

EnterprisEnterprisee

StandardStandard Workgroup, Workgroup, ExpressExpress

Failover ClusteringFailover Clustering YesYes 2-node2-node NoNoDatabase MirroringDatabase Mirroring YesYes Safety Safety

FullFullWitness Witness onlyonly

Database SnapshotsDatabase Snapshots YesYes NoNo NoNoSnapshot IsolationSnapshot Isolation YesYes YesYes YesYesOnline Index Online Index OperationsOperations

YesYes NoNo NoNo

Fast RecoveryFast Recovery YesYes NoNo NoNoDedicated Admin Dedicated Admin Conn.Conn.

YesYes YesYes No on ExpNo on Exp

Table PartitioningTable Partitioning YesYes NoNo NoNoLog ShippingLog Shipping YesYes YesYes No on ExpNo on ExpPeer-to-Peer Peer-to-Peer ReplicationReplication

YesYes NoNo NoNo

New York! New York!New York! New York!איך ממלאים משוב?איך ממלאים משוב?

בסוף כל יום בסוף כל יום emailemailב - ב - Beat CenterBeat Centerב -ב -

מה מקבלים?מה מקבלים?Feel The BeatFeel The Beatחולצת חולצת

השתתפות בהגרלת כרטיסי טיסההשתתפות בהגרלת כרטיסי טיסה)לממלאים משוב לכל יום()לממלאים משוב לכל יום( ועוד... ועוד...i-matei-mateמכשירי מכשירי

The Prime Grill - SteakhouseThe Prime Grill - Steakhouse

Assaf Fraenkel

60 east 49th st. New York, NY

2126929292

הכשריםהסטייקים בניו- יורק הטובים

ועוד במנהטן!!

HAHAהרצאות מומלצות בנושא הרצאות מומלצות בנושא

Isolaion LevelIsolaion Level עמי לוין בנושא עמי לוין בנושא 11:3011:30היום ב היום ב replicationreplication מאיר דודאי בנושא מאיר דודאי בנושא 8:308:30מחר ב מחר ב

Summary – What is Summary – What is Availability?Availability?

Download - Assaf Fraenkel Principal Consultant Microsoft Consulting Services High Availability with SQL 2005 זמינות יתרה והמשך פעילות עסקית

Top Related