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Advanced Configuration Options
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Objectives
At the end of this module, you should be ableto do the following:• Describe use of a shared application tier file system in
Oracle Applications• Explain the benefits of using a staged APPL_TOP• Identify the main load balancing options and their key
features• List the major factors in efficient network design for Oracle
Applications
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Module Overview
This module discusses the following topics:• Shared Application Tier File System• Load Balancing Options• Network Features
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Shared Application Tier File System - Introduction
A shared application tier file system is a single Application tier file system that can be accessed simultaneously from more than one machine:• The application tier file system disk is attached to a mount
point of the same name on all machines
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Shared Application Tier File System – Not In Use
Without a shared application tier file system, each application tier node has its own file system, which must be managed independently:
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Shared Application Tier File System – In Use
With a shared application tier file system, all application tier nodes share a single file system, which simplifies maintenance:
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Shared Application Tier File System – Features
A shared application tier file system can be used for all nodes in an application tier:• In Release 12, all application tier file systems contain the
same installed files• An application tier can be shared immediately
– It is not necessary to start from scratch• Specific sharing technologies are not certified
– The shared file system must simply be accessible from all nodes
• The Release 12 Rapid Install can install a shared application tier file system
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Shared Application Tier File System – Benefits
Using a shared application tier file system has several benefits:• Machines can easily be added to an existing system in order
to: – Maximize system availability– Cater for additional usage requirements
• Disk space requirements are greatly reduced.• Administrative tasks need only be carried out
once, on any node
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Shared Application Tier File System - Availability
Using a shared application tier file system offers several advantages in the area of high availability: • An Applications patch only needs to be applied once,
minimizing downtime• It is easier to add nodes, to cater for more users and provide
greater resilience
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Load Balancing – Introduction
The various Applications technology layers can be distributed across a larger or smaller number of machines, according to:• Physical topology• Required performance• Desired expenditure
Other possible factors include:• Growth in user base• Fluctuations in demand• Resilience in the event of hardware problems
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Load Balancing – Strategic Effect
Load balancing involves the entire infrastructure of an Oracle Applications installation:• Performance can often be improved using existing hardware• A change in one area can potentially have effects elsewhere
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Load Balancing – Areas
Principal load balancing areas include:• Domain Name Server• HTTP Server• Concurrent Processing Layer• Database Layer
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Load Balancing – Session Persistence
The two main categories of load balancer are:• Session Persistent Load Balancers, which always direct
HTTP requests from a client to the same server– Client connections are session-persistent– This is also referred to as stickiness
• Non-Session Persistent Load Balancers, which do not necessarily direct HTTP client requests to the same server
– Client connections are not session-persistent
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Load Balancing – SSL Accelerators
Another type of load balancer uses Secure Sockets Layer (SSL) Accelerators, which:• Reduces the SSL traffic and workload of the Web server• Converts SSL HTTPS client browser requests to non-SSL
HTTP requests• Directs subsequent request to the HTTP server
A reverse of this process is used to send the response back to the browser
SSLAccelerator
HTTPS
HTTPS HTTP
HTTP
Web Server
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Load Balancing – Specific Options
Several different types of load balancing can beemployed with Oracle Applications:• They range from the relatively simple to the more
sophisticated• The load balancing solution should integrate with the existing
infrastructure of a site
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Load Balancing – DNS Layer
DNS Layer LoadBalancing distributesrequests based ondynamic assignmentsof IP addresses to afully qualified domainname:
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Load Balancing – HTTP Layer
HTTP Layer LoadBalancing requires ahardware load balancerthat accepts HTTPcommunication andforwards it to a group(farm) of server nodes:
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Load Balancing – Concurrent Processing Layer
Parallel Concurrent Processing (PCP) enables you to:• Run concurrent processes on multiple nodes to improve
concurrent processing throughput• Continue running concurrent processes on the remaining
nodes when one or more nodes fail• Administer concurrent managers running on multiple nodes
from any node in the clusterPCP is enabled by default, so is always available for use
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Load Balancing – Database Layer
Oracle Real Application Clusters (Oracle RAC) harnesses the processing power of multiple computers:• All active instances can concurrently execute transactions
against a shared database• Oracle RAC coordinates each instance's access to the
shared data, to provide data consistency and integrity• All E-Business Suite modules can be successfully deployed
against an Oracle RAC-enabled database
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Network Features – Introduction
When deploying a global IT infrastructure, the choice of network topology can be critical. There are a number of significant strategic factors:• Basic structure• Latency• Satellite Links• Wireless LANs
Each of these will be discussed briefly on the following slides
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Network Features – Strategies
A large organization will typically use a hub and spoke network topology:• High-capacity links serve regional hubs, with medium-
capacity connections to local offices• The routes and hops need to be as short and efficient as
practicable
High-capacity linkMedium-capacity link
Regional hubLocal office
Example Network Topology
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Network Features – Latency
Latency is the time for a packet to travel from its source to its destination, and can be significant:• Oracle Applications works well with average latencies up to
300ms– Performance is generally acceptable with latencies up to
500ms• Where latency is marginal, forms may be slower to load (for
example, on startup)– In such circumstances, HTML-based applications may give
better performance than Forms-based applications
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Network Features – Satellite Links
Satellite links can be used as a network link for Oracle Applications:• They are considered to be just another network type• They may be the only choice for users in remote locations• They should only be employed where use of terrestrial
services is not feasible• The network stack may need to be tuned
The goal is to achieve reliable operation, while maintaining an acceptable response time
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Network Features – Wireless LANs
As well as security aspects, deployment of wireless technology must take into account technical considerations, including:• Overall stability of the connection• Momentary loss of service may occur as a result of:
– Not having the latest firmware revision– Interference from devices using a similar wavelength, such as
cordless phones• Use of Forms Listener Servlet (the default in Release 12),
with its capability to attempt reconnection
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Network Features – Wireless LANs
Wireless LANs are simply considered as another network topology, so are not explicitly supported (or unsupported) with Oracle Applications• A problem should if possible be reproduced using a non-
wireless link• If it cannot be reproduced, the wireless link will need to be
checked
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Module Summary
In this module, you should have learned howto do the following:• Describe the advantages of using a shared application tier
file system• Identify the main load balancing options and their key
features• List the major factors in efficient network design for Oracle
Applications
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Module Discussion
• Summarize the features offered by a shared application tier file system
• List three possible benefits of load balancing• Describe the effect of latency on a network, and how it
affects Oracle Applications• Why does use of the Forms Listener Servlet often help with
network operation?