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The benefits of using the software are many in any environment dealing with data. It ensures that the data stays protected and easily available. You get to take the load off from backups to the standby operations database. The problems like gaps in the standby database are automatically detected and resolved. The guard broker allows automated role transition.
The three top services offered by the software are:
The three protection modes that are available include maximum availability, protection, and performance.
The default mode in the software Data Guard is Maximum performance.
The main advantage of this default mode is that the performance of the primary data is not affected while the highest possible level of protection for the data is ensured. The transactions begin to commit as soon as the redone data produced by the transactions get written onto the online log.
This protection mode comes to the rescue when the primary database fails. The primary database shuts down and stops processing the transaction when this protection mode is enabled. So with this protection mode, you can be assured that there will be no data loss.
The redone data must get written in two places before committing the transaction- the online log and a standby database. This way the primary database can shut down but the data remains intact.
The biggest advantage with one is that the availability of the primary database is uncompromised but the maximum possible level of protection is offered to the data. The transactions with this protection mode only commit when all the redone data needed to recover the transactions get written to a standby database and the online log.
The steps for changing the protection mode are as follows:
It depends on what version of the software is at your disposal. The general number ranges from nine to thirty standby databases.
The following easy steps can create a physical standby in the software:
There is a fourfold advantage to using the physical database standby.
Four basic services are required on the primary database. They are as follows:
There are four services required on standby:
The standby gets naturally applied to the redo logs at the time of their arrival from the primary database. There are times when a time lag is needed to be created between archiving a redo log at the primary point and applying the log at standby.
You need to modify the parameter for initialization on the primary site to lead to a delay on the standby site. For instance, if you want a delay of one hour, you can set the log for delay at sixty minutes. It is worth mentioning in this regard that the delay is always given in minutes in the format of, for instance, 60′.
With this action, the redo logs are still copied from the primary to the standby site but it does not immediately apply. They get applied after the expiry of the specific time interval that has been set.
It is used for controlling the automatic transmission of redo data of the production database in one or multiple archives. The following tasks are successfully performed by it:
The biggest difference between the two databases is the way of application of services to the archived redo files.
For the physical database, the software has a technology called Redo Apply. This one applies the redo on the standby system by the use of the basic recovery technique of the software. For the standard database, the software uses a technology called SQL. This one first transforms the redo it receives into statements and afterward the execution of the statements on the standby system is initiated.
The Broker helps in the management of standby and primary bases by the utilization of command-line, broker, or graphical interfaces. These are integrated into the Enterprise Manager software by Oracle.
It can be used to provide five benefits which have been listed below:
The logical database is created similar to the physical and standby database. The structure of the logical database can get altered at a later point in time. The sync with standby and the primary is made easy by the utilization of SQL. The received logs of redo are made into statements and they are continuously applied into logical databases. This way the standby system is made consistent with the primary. The report of purpose is made easier with logical standby as compared to the physical one. The logical database is available in both read-write modes. The tables that are in sync with primary data are made available in read-only operations only. So you get the availability on some queries, index adding, and reporting.
The only major disadvantage that this one has is in the matters of types of tables and a few of the data functions. On the overall aspects, it is held as having an advantage over the physical database.
There are certain automated features that are not available in the standard edition. You can ship logs and write the scripts manually to get the steps done. On certain platforms, you get to write the scripts and then use the commands to ship it to the standby system. The recovery is then carried out manually and it is removed after the application is done.
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The software is a huge advantage in firms that require the handling of large amounts of data. The certification in this software helps to smoothen out the large data processes. You can save the corruption of data and provide ease of data recovery. The trained professional becomes an inevitable asset to the company whenever it goes through any kind of data emergency. The basic yet complicated job of data backup and processing is made easy by the use of the software. The trained professional in this software is an important troubleshooter for the company which is what gives a person a professional advantage in the current scenario.
The apply services refer to the application of the redo data on the standby system to keep the transactional sync with the primary system. This redo data can get applied from either archived redo files or from the standby redo files directly as they get filled. The application from the standby redo files is only possible if the real-time facility gets enabled. It does not require the redo log to get archived at the standby system first. One of the main features of this service is that it also permits read-only accessibility to the data.
Ravindra Savaram is a Content Lead at Mindmajix.com. His passion lies in writing articles on the most popular IT platforms including Machine learning, DevOps, Data Science, Artificial Intelligence, RPA, Deep Learning, and so on. You can stay up to date on all these technologies by following him on LinkedIn and Twitter.