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9.5.4.3 Extended Remote Copy ..................................99
9.5.5 Compression..........................................100
9.5.6 Sequential Data Striping . ................................101
Chapter 10. DB2 I/O Operations .................................103
10.1 AvoidingI/OOperations ....................................103
10.2 DataReadOperations .....................................104
10.2.1 NormalRead.........................................104
10.2.2 Sequential Prefetch....................................104
10.2.3 DynamicPrefetch.....................................105
10.2.4 ListPrefetch.........................................105
10.2.5 Prefetch Quantity .....................................105
10.2.6 Data Management Threshold . ...........................106
10.2.7 Sequential Prefetch Threshold ...........................107
10.3 DataWriteOperations......................................107
10.3.1 Asynchronous Writes . . ................................107
10.3.2 Synchronous Writes . . . ................................108
10.3.3 ImmediateWriteThreshold..............................108
10.3.4 Write Quantity . . ......................................108
10.3.5 Tuning Write Frequency ................................108
10.4 LogWrites ..............................................111
10.4.1 Asynchronous Writes . . ................................112
10.4.2 Synchronous Writes . . . ................................112
10.4.3 Writing to Two Logs....................................112
10.4.4 Two-PhaseCommitLogWrites...........................112
10.4.5 ImprovingLogWritePerformance.........................114
10.5 Log Reads . . . ...........................................115
10.5.1 ImprovingLogReadPerformance.........................116
10.5.2 ActiveLogSize.......................................117
Chapter 11. I/O Performance and Monitoring Tools .................119
11.1 DB2PMOverview.........................................119
11.1.1 Accounting I/O Information . . . ...........................120
11.1.1.1I/OOperations .......................................120
11.1.1.2 I/O Suspensions......................................121
11.1.2 StatisticsI/OInformation................................121
11.1.2.1DataI/OOperations...................................121
11.1.2.2LogActivity..........................................122
11.1.3 PerformanceI/OInformationandI/OActivity.................123
11.2 RMFMonitoring ..........................................124
11.2.1 RMF Report Analysis . . ................................125
11.2.1.1 Cache Subsystem Activity Reports . . . ....................125
11.2.1.2DirectAccessDeviceActivityReport......................128
11.2.2 Using RMF Reports....................................132
11.2.2.1ResourceLevelAnalysis ...............................132
11.2.2.2 RMF Reporting at Storage Group Level....................133
11.2.2.3ToolsProvidingMoreIn-DepthAnalysisthanRMF...........133
11.2.2.4 Spreadsheet Tools for RMF Analyzis. . ....................133
11.2.2.5 Global View of a DB2 I/O by DB2 PM and RMF .............134
11.3 IXFPMonitoring ..........................................135
11.3.1 Device Performance Reports. . ...........................136
11.3.2 Cache Effectiveness Report . . ...........................137
11.3.3 Space Utilization Report ................................138