CAPITULO II: MARCO METODOLÓGICO
2.5. Técnicas de procesamiento y análisis de datos
Infrastructure
For OracleAS Disaster Recovery Release 10.1.2.0.1, only the OracleAS Disaster Recovery symmetrical topology environment was supported. This OracleAS Disaster Recovery environment has two major requirements:
■ The deployment must use a single default Infrastructure install that contains a collocated OracleAS Metadata Repository and Oracle Identity Management. ■ The standby site has to be a strict mirror of the production site with the same
number of instances (symmetrical topology).
Figure 5–1 depicts an example OracleAS Disaster Recovery solution having a symmetrical topology with a Cold Failover Cluster on the primary site. This is considered a symmetrical topology because from an Oracle Application Server perspective both sites contain two OracleAS middle tiers and one Infrastructure.
Figure 5–1 Example Oracle Application Server Site-to-Site Disaster Recovery Solution (Load Balancer Appliance Is Optional If Only One Middle-Tier Node Is Present)
The procedures and steps for configuring and operating the OracleAS Disaster
Recovery solution support 1 to n number of middle-tier installations in the production site. The same number of middle-tier installations must exist in the standby site. The middle tiers must mirror each other in the production and standby sites.
For the OracleAS Infrastructure, a uniform number of installations is not required (names or instances must be equal) between the production and standby sites. For example, the OracleAS Cold Failover Cluster (Infrastructure) solution can be deployed in the production site, and a single node installation of the OracleAS Infrastructure can be deployed in the standby site as shown in Figure 5–1. This way, the production site's OracleAS Infrastructure has protection from host failure using an OracleAS Cold Failover Cluster. This solution provides hardware redundancy by utilizing a virtual hostname. Refer to the Section 6.2.2, "Active-Passive High Availability Topologies" on page 6-5 of the Oracle Application Server High Availability Guide in the OracleAS Release 10.1.2.0.2 documentation set for more information on OracleAS Cold Failover Clusters. The OracleAS Disaster Recovery solution is an extension to various single-site Oracle Application Server architectures. Examples of such single-site architectures include the combination of OracleAS Cold Failover Cluster (Infrastructure) and active-active Oracle Application Server middle-tier architecture. For the latest information on what single-site architectures are supported, check the Oracle Technology Network (OTN) Web site for the latest certification matrix.
http://www.oracle.com/technology/products/ias/hi_av/index.html
The following are important characteristics of the symmetric OracleAS Disaster Recovery solution: Load Balancer OracleAS Middle Tier OracleAS Middle Tier OracleAS Cold Failover Cluster (Infrastructure) (Standby) (Active) Shared Storage Node 1
Primary / Active Site
Node 2 Load Balancer OracleAS Middle Tier OracleAS Middle Tier OracleAS Infrastructure Node 1
Secondary / Standby Site
Oracle Application Server 10g Disaster Recovery Solution
■ Middle-tier installations are identical between the production and standby sites. In other words, each middle-tier installation in the production site has an identical installation in the standby site. More than one middle-tier node is recommended because this enables each set of middle-tier installations on each site to be
redundant. Because they are on multiple machines, problems and outages within a site of middle-tier installations are transparent to clients.
■ The OracleAS Disaster Recovery solution is restricted to identical site
configuration to ensure that processes and procedures are kept the same between sites, making operational tasks easier to maintain and execute. Identical site configuration also allows for a higher success rate for manually maintaining the synchronization of Oracle Application Server component configuration files between sites.
■ When the production site becomes unavailable due to a disaster, the standby site can become operational within a reasonable time. Client requests are always routed to the site that is operating in the production role. After a failover or switchover operation occurs due to an outage, client requests are routed to another site that assumes the production role. For a symmetric topology, the quality of service offered by the new production site should be the same as that offered by the original production site before the outage.
■ From the standpoint of a single site, the sites are set up in active-passive
configuration. An active-passive setup has one primary site used for production and one secondary site that is initially passive (on standby). The secondary site is made active only after a failover or switchover operation is performed. Since the sites are symmetrical, after failover or switchover, the original standby site can be kept active as the new production site. After repairing or upgrading the original production site, it can be made into the new standby site as long as the OracleAS Disaster Recovery site requirements are maintained. Either site should offer the same level of service to clients as the other. Note that in an active-passive setup, the standby site can be comprised of different Oracle homes that can be active on the same hosts as long as the Oracle homes being used in the Disaster Recovery environment are passive (inactive).
■ For a database recovery (DBR) site as explained shortly (an OracleAS 10g release (10.1.3) site is most likely not involved, whereas an OracleAS 10g release
(10.1.2.0.2) site is involved), the site playing the standby role contains a physical standby of the Oracle Application Server Infrastructure coordinated by Oracle Data Guard. OracleAS Guard automates the configuration and use of Oracle Data Guard together with procedures for backing up and restoring OracleAS
Infrastructure configuration files and provides configuration synchronization between the production and standby sites. Switchover and failover operations allow the roles to be traded between the OracleAS Infrastructures in the two sites. Refer to Section 5.10, "OracleAS Guard Operations -- Standby Site Cloning of One or More Production Instances to a Standby System", Section 5.11, "OracleAS Guard Operations -- Standby Instantiation and Standby Synchronization", Section 5.12, "Runtime Operations -- OracleAS Guard Switchover and Failover Operations", and Section 5.15, "Using OracleAS Guard Command-Line Utility (asgctl)" for information about using the asgctl command-line interface to perform OracleAS Guard administrative tasks of cloning, instantiation, synchronization, switchover, and failover in the OracleAS Disaster Recovery solution.