COMP283-Lecture7

AppliedDatabaseManagement

Introduction

HighAvailability ServerMaintenance

Redundancy

MitigationPlan

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COMP283-Lecture7DBAdministration:BackupsandRestore● Backup,Backup,Backup!● DatabasebackupandSystembackup

● Setabackupschedule.● Onaregularbasis.

● Verifybackupsareworking.● How?

● Storebackupssecurely

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COMP283-Lecture7DBAdministration:BackupScheme● Backupsshouldneverbetothesamediskasthedataorsystemfiledisks.●Whynot?

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COMP283-Lecture7DBAdministration:BackupScheme● Identifyabackup● Determinewhenabackupcanbereplaced/overwritten● Typesofbackups:● FullBackup● DifferentialBackup● Recordsallthechangessincethepreviousfullbackup

● IncrementalBackup● Recordsthechangessincethepreviousincrementalbackup

● Identify/labelallbackupsonthebackupmedium�4

COMP283-Lecture7DBAdministration:BackupStrategies● On-lineBackup● Immediatelyavailableforrecovery

● Near-lineBackup● Filesnotimmediatelyavailable,butcanbemadeavailableeasily.

● Off-lineBackup● Toaremoteserverorremovablemedia.

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COMP283-Lecture7DBAdministration:BackupStrategies

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COMP283-Lecture7DBAdministration:BackupStrategies

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COMP283-Lecture7DBAdministration:BackupStrategies● MostDBMShaveutilitiestocreatebackups● e.g.mysqldump

● Manyoftheseare“commandline”programs-canbeplacedintoascript

● CanuseOStoschedulebackups● e.g.unix/linuxcronsystem

●

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15 2 * * * root mysqldump -u root -pPASSWORD --all-databases |

gzip > /mnt/disk2/database_`date ' %m-%d-%Y'`.sql.gz

COMP283-Lecture7DBAdministration:BackupStrategies●Whentobackup?● CheckpatternofuseofDB/System● Lookfortimesoflittle/lowuse● Overnight?Weekends?● Perhapsdoadifferentialorincrementalbackuptoreducedowntime.Dofewerfullbackups.

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COMP283-Lecture7ServerMaintenance:MitigationPlans● twomaintypesofmitigationplans:● DisasterRecoveryandBusinessContinuity

● Bothrequire:● Uptodatecontactlist● Decisiontreeforvariousscenarios● Infoonrecoveringadminusernamesandpasswords● Detailsonbackups● Systemconfigurationinfo● Definitionofasuccessfulrecovery

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COMP283-Lecture7ServerMaintenance:MitigationPlans● DisasterRecoveryPlan:Howwillyoudealwithatotallossofdata,equipmentorinfrastructure?

● Essentialthatyouhave:● Assetinventory● Adequateinsurance● Backups● Systemconfigurationdetails● Detailsofessentialinfrastructureandequipment.

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COMP283-Lecture7ServerMaintenance:MitigationPlans● BusinessContinuityPlan:Howwillyoucopewithlossofemployeesorbusinesspartners,businessrestructuringorreorganisation,businesstakeovers,andsystemsmaintenance.

●Whathappenswhenthekeypersonnelleave?● SystemMaintenancePlan:● Usergroup-consultformaintenanceschedule● UsersmustcheckDBaftere.g.updatestoOS/DBMS

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COMP283-Lecture7ServerMaintenance:ServerPerformance● SomeDBMSsystemsincludefacilitiestomonitortheirownperformance.

● Alternatively,OStoolswillallowyoutomonitorthehealth/utilisationofe.g.thediskandreportwhenitisgettingfull.● e.g.onUnix/Linuxsystemdureportsdiskusage,topdisplaysprocessstats

● maybeusedaspartofascript● Monitoredovertime,youcangetafeelforwhetherthesystemistunedcorrectly.

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COMP283-Lecture7ServerMaintenance:ServerPerformance●WindowsManagementInstrumentation(WMI)isaWindowssystemsmanagementsuiteoftools.

● MS-SQLServersupportsalertsbasedonWMIevents.● LinuxandUnixbasedDBMS-typicallyyouhaveto“rollyourown”● Oracle(theDBMScompany)sellacompleteLinuxsystemwhichincludestheirDBandtoolstoadministerit.

● Howeverit’sdoneyougenerallycan’tjustsetupyourdatabase(andserver)andforgetit.

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COMP283-Lecture7Conclusions● Introducedservermaintenance:● Failureplanningandmitigation(includingBackups!)● Maintenanceplanning

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