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Natik Ameen Session #352

Oracle 11g Real Application Clusters Advanced Administration. Natik Ameen Session #352. Introduction. Natik Ameen , Senior Oracle DBA DBA for 8 years, with 4 years on RAC 9i, 10g Financial, Gaming and Aviation industries

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Natik Ameen Session #352

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  1. Oracle 11g Real Application Clusters Advanced Administration NatikAmeenSession #352

  2. Introduction • NatikAmeen, Senior Oracle DBA • DBA for 8 years, with 4 years on RAC 9i, 10g • Financial, Gaming and Aviation industries • Intended for everyone who has basic knowledge of RAC

  3. Objective • RAC overview • ASM • Nodeapps • Metrics collection • Wait events • Best Practice • 11g New features

  4. RAC Overview • Clustered nodes • Cluster Interconnect • Virtual IP • Shared storage • NodeApps

  5. RAC Architecture • Clustered nodes • Interconnect Network • Shared storage

  6. SGA Structure & Processes • Global Resource Directory : Maintains mapping of data in SGA • Global Cache Server: Synchronizes Buffer cache across instances • Global Enqueue Services: Maintains coherency in data dictionary & library caches • Lock Manager Server:Transports blocks for Cache Fusion between nodes.

  7. Cache Fusion • What is it • Concurrency & Consistency • Scalability

  8. Interconnect Network • Main component for “Cache Fusion” • IC uses private network • User Datagram Protocol(UDP) • Reliable Datagram Socket Protocol(RDS) > 10.2.0.3 • Typical bandwidth utilization 20-30%, saturated > 70%

  9. ASM Overview • ASM Instance • Disk Group • Disk Files • ASMLib

  10. ASM Instance • Scaled down version of DB instance • DB instance access DB files

  11. Disk Groups • Striping • Mirroring • Failure groups

  12. ASM Files • Name pre-pended with ‘+’

  13. ASMLib • Kernel driver with efficient access to DB files

  14. NodeApps • Listener • Oracle Notification Services • Fast Application Notification • Fast Connection Failover

  15. Metrics Collection • AWR Reports • OS Utilities • Bench Marking

  16. AWR Report The RAC specific statistics include: • Instance Global Cache Load Profile • Global Cache Efficiency percentages • Messaging Statistics • Top % CR and Current Block Segments

  17. Cache Fusion data block & messaging traffic Calculate network traffic

  18. RAC Wait Events Most of these wait events occur during Cache Fusion • GC cr/current block 2-way, 3-way • GC cr/current block congested • GC cr/current block busy • GC current grant busy • GC cr/current block request • GC cr block lost

  19. GC wait events • Classified under “cluster wait lass”. • Characterized as “current” or as “CR”. • “current” classified as all blocks read into memory for the very first time • CR denotes block for read access • Master node maintains complete information on the resource, others maintain information on locally held locks

  20. gc current block 2-way Instance A requests block from master instance B If the block is available on B then it is sent to A

  21. gc current block 3-way • Instance A requests block from master instance B • B does not have block but directs instance holding block • or directs request to disk • Three hops maximum, not dependant on number of nodes

  22. GC cr/current block congested • Repeated requests by foreground processes, not serviced by LMS • Indicates LMS not able to keep up • Queue lengths & scheduling delays in OS, can cause LMS delays GC cr/current block busy • Delay for some reason, before block sent to requestor • Could be due to I/O saturation GC current grant busy • Permission to access the block granted, but blocked by other requests ahead of it GC cr/current block request • Wait time, when cr or current block is being retrieved GC block lost • Lost blocks possibly due to faulty interconnect network

  23. Where to get more information • Other sessions here at IOUG-A Live! • RAC Special Insterest Group(RAC SIG) • Consulting companies (depending on specialization)

  24. Questions? • Lots of things to cover • If we didn’t cover something you wanted to hear, please contact me

  25. Oracle 11g Real Application Clusters Advanced Administration THANK YOU! Please fill out evaluations!

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