Real Application Clusters

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Real Application Clusters

• Kunal Bansal
• kbansal_at_cs.odu.edu

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Overview

• Clusters
• Architecture of RAC
• Installation and Configuration
• Instance, Storage and Performance Management
• Advantages Disadvantages
• Automatic Workload Management
• Cluster Verification and Performance Improvement
• Improvement in 10g over 9i RAC
• Conclusion

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Clusters

• A cluster is a group of independent servers that
  cooperate as a single system with the primary
  cluster components being processor nodes, a
  cluster interconnect and a shared disk subsystem.
  
• The clusters share disk access and resources that
  manage data, but the distinct hardware cluster
  nodes do not share memory.
• A cluster can be made up of multiple
  single-processors known as SMP nodes where each
  node has its own dedicated system memory, own
  operating system, database instance, and
  application software.

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Architecture of RAC
ORACLE REAL APPLICATION CLUSTER SYSTEM
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Architecture of RAC (Cont)

• An Oracle RAC system is composed of a group of
  independent servers, or nodes, that cooperate as
  a single system as shown in the previous slide.
• These nodes have a single view of the distributed
  cache memory for the entire database system.

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Installation

• Installation is done using the same tools used to
  setup a single instance database and OUIs
  cluster extension automatically detects if the
  environment is a cluster and which all nodes are
  a part of it.
• The Oracle installer presents the list of all
  cluster nodes, allows a subset to be chosen as
  targets, copies the Oracle software onto the
  first node and then propagates the software onto
  the rest of the chosen nodes of the cluster.
• With version 9.2 DBCA allows the use of raw
  devices or cluster file system files as datafiles
  for your cluster database.
• DBCA also simplifies the task of adding a new
  node to a cluster.

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Configuration

• DBCA is automatically launched at the end of the
  installation to configure the database and uses
  standard placement practices such as the OFA.
• Entire cluster database or a selected set of its
  instances and their related services (like
  listeners) can be started or shutdown as a single
  operation with Oracle Enterprise Manager.
• Real Application Clusters environments, resource
  management configuration allows each instance to
  use a different resource plan so that resources
  on the node where an instance runs can be
  utilized efficiently. They can be activated and
  monitored individually at the cluster instance
  level.

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Storage Management DATAFILES REDOLOGS

• Real Application Clusters option requires that
  all instances access unformatted devices on a
  shared disk subsystem, also referred to as raw
  devices.
• The instances write data onto the raw devices to
  update the data files, control files, and redo
  logs that all nodes in the cluster share.
• Datafiles on raw devices can be taken off line
  or, you can view their associated tablespaces and
  their size. Since raw partitions are physically
  created with a fixed size, the "autoextend"
  option does not apply.

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Storage Management
BACKUP

• Backup and Recovery wizards are designed to help
  DBAs create scheduled backups and specific types
  of recovery.
• Backing up and recovering a Real Application
  Cluster database is done with Enterprise Manager
  creating jobs that prepare the cluster database
  based on the specified backup strategy and allows
  recovery to be performed when needed.
• Pre-defined backup strategies can be used which
  range from a complete to specific tablespaces and
  datafiles backup and recovery, configuration of
  backups with different attributes or viewing and
  editing the backup configurations already created
  in the Backup Configuration Library
• For jobs that fail, Enterprise Manager can be
  setup to trigger an email or page to be sent to
  the database administrator.

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Storage Management 10g END TO END
RECOVERY

• Oracle RAC 10g enables fast, coordinated recovery
  between the database and application mid-tier
  components and products.
• Oracle RAC 10g integrated clusterware detects
  when instances and nodes go down and when they
  come back up. A highly adaptable notification
  system transmits UP and DOWN signals to the
  application mid-tier immediately so that
  appropriate self-correcting recovery procedures
  can be applied.
• With JDBC Fast Connection Fail-Over, the DOWN
  notification signal initiates processing to clean
  up bad connections from the JDBC connection cache
  and prevents bad or invalid connections from
  being handed out to application work requests.

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Performance Management

• Database performance depends on many factors,
  including effective use of memory, minimizing
  disk I/O, and avoiding resource contention.
• Administrators can obtain statistics that
  represent the aggregate performance of all
  instances of a cluster database.
• Among the Real Application Clusters performance
  metrics that can be viewed, are
• Global Cache Converts
• Global Cache Gets
• Global Cache Blocks Lost
• Global Cache Blocks Corrupt

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Advantages

• It exploits modern hardware and software
  clustering technologies to provide the most
  flexible cluster database platform.
• Ensures high availability of server with
  uninterrupted service regardless of hardware
  and/or software failures.
• Can take advantage of additional equipment and
  harness the processing power of multiple systems.
• Applications that run on single instance Oracle
  execute with the same results using Real
  Application Clusters.
• It supports all Oracle backup features that are
  available in exclusive mode, including both
  online and offline backups of either an entire
  database or individual tablespaces.

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Disadvantages

• File Migration.
• Certain File Types Cannot Be Shared.
• Key Oracle9i Features Cannot Be Used.
• Inferior I/O Fencing.
• Data Duplication and Back-up Overhead.
• Cluster Size Limitations.
• Throughput Limitations.
• Inferior I/O Fencing and Server Recovery.

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Automatic Workload Management 10g

• With Oracle Database 10g, application workloads
  can be defined as services so that they can be
  individually managed and controlled.
• In Oracle Database 10g, rules can be defined to
  automatically allocate processing resources to
  services during normal operations and when
  failures occur.

EXAMPLE OF SERVICE PROVISONING ACROSS 6 NODE
CLUSTER
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Cluster Verification 10g

• Oracle Database 10g introduces a new cluster
  configuration verification tool and improvements
  in the diagnostic tools first introduced in
  Oracle9i.
• The tool is invoked through a command line
  interface or through an API by other programs
  such as OUI, OEM, DBCA, and ASM.
• Diagnostic tools have been improved to further
  speed problem resolution times, reduce the need
  to reproduce problems, improve ease of use, and
  minimize database overhead in both RAC and
  non-cluster environments.

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Performance Improvements 10g

• The Fast Connection Fail-Over feature described
  above also enables fast, coordinated recovery
  between the database and application mid-tier
  components and products.
• Message aggregation improves the efficiency of
  CacheFusion communication between nodes by
  combining multiple messages into one when
  appropriate.
• Dynamic resource re-mastering is another
  important optimization which is caused when
  applications consisting of multiple workloads
  exhibit a high degree of affinity to certain sets
  of data resources.

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New Features in RAC 10g

• Elimination of the need for 3rd party software
  components that add significantly to the
  complexity and cost of cluster environments by
  providing a full stack Oracle solution.
  Management of cluster environments as a single,
  integrated system image.

INTEGRATED CLUSTERWARE MANAGEMENT IN ORACLE RAC
10g
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New Features in RAC 10g (Cont)

• Automation of key functions such as workload
  management that previously had to be done
  manually.
• Improved integration with all other Oracle
  features and functions so that they fully and
  transparently support RAC environments.
• New and improved tools to verify the correctness
  of cluster configurations and help pinpoint the
  source of problems quickly.
• Performance improvements that will benefit many
  applications.
• Zero downtime patches for Oracle RAC cluster
  environments.

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Conclusion

• The Oracle Database 10g, and the specific new
  manageability enhancements provided by Oracle RAC
  10g, enable Enterprise Grids and RAC for
  everyone - the ubiquitous adoption of Oracle RAC
  by all types of businesses for all types of
  applications.
• Enterprise Grids are built from large
  configurations of standardized, commodity-priced
  components processors, network, and storage and
  with Oracle RACs cache fusion technology, the
  Oracle Database add to this the highest levels of
  availability and scalability
• With Oracle Database 10g and Oracle RAC 10g
  dramatically reducing operational costs still
  further, new levels of flexibility become
  possible through dynamic provisioning of nodes,
  storage, CPUs, and memory to maintain service
  levels more easily and efficiently while lowering
  cost still further through improved utilization.

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References

• Oracle9i Real Application Clusters Business
  Whitepaperhttp//www.oracle.com/technology/produc
  ts/database/clustering/pdf/Oracle9iRAC_BusinessWhi
  tePaper.pdf
• Managing Oracle9i Real Application Clusters
• http//www.oracle.com/technology/products/databas
  e/clustering/pdf/managing_rac_rel2.pdf
• Database Support and integration with RAC Sachin
  Sharma
• http//www.dbasupport.com/oracle/ora9i/rac.shtml
• Oracle RAC System
• http//www.datadirect.com/techzone/dotnet/topics/
  oracle_rac_for_net/index.ssp

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End of Presentation