Oracle Database 11g Dataguard Implementation Manual

What is a DataGuard ?

Oracle DataGuard ensures high availability, data protection, and disaster recovery for enterprise data. Data Guard provides a comprehensive set of services that create, maintain, manage, and monitor one or more standby databases to enable production Oracle databases to survive disasters and data corruptions. Data Guard maintains these standby databases as transactionally consistent copies of the production database. Then, if the production database becomes unavailable because of a planned or an unplanned outage, Data Guard can switch any standby database to the production role, minimizing the downtime associated with the outage. Data Guard can be used with traditional backup, restoration, and cluster techniques to provide a high level of data protection and data availability.

Preparing the PRIMARY Database:-

On the primary database, make sure you have set values for the following parameters, which impact the transfer of the redo log data. The first three parameters, listed next, are standard for most databases.

  1. DB_NAME: The database name. Use the same name for all standby databases and the primary database.
  2. DB_UNIQUE_NAME: The unique name for the database. This value must be
    different for each standby database and must differ from the primary database.
  3. SERVICE_NAMES: Service names for the databases; set separate service names for the primary and standby databases.

Continue reading

Installing Oracle Golden Gate

What is Oracle Golden Gate?

Oracle GoldenGate 12c offers a real-time, log-based change data capture (CDC) and replication software platform to meet the needs of today’s transaction-driven applications. The software provides capture, routing,
transformation, and delivery of transactional data across heterogeneous environments in real time. Oracle GoldenGate only captures and moves committed database transactions to insure that transactional integrity is maintained at all times. The application carefully ensures the integrity of data as it is moved from the source
database or messaging system, and is applied to any number of target databases or messaging systems.

Oracle Goldengate supports the replication of data across various heterogeneous platforms. The Goldengate replication topology includes the capture and transfer of the extracted data from the source database, across to the destination database.

Continue reading

Creating a local repository

 

Let’s create a yum repository from the packages that we have in the Red Hat/Centos installation DVD. Creating a YUM repository will help you to understand the concept of a YUM repository closely.

You get a large number of packages(development tools & application packages etc), inside the installation disk. However all are not installed, when you install the operating system.

Later on if you need a particular package, its not at all advisable to insert the installation disk once again, and fetch that required .rpm package and install it. Again if you face dependency problems, you need to fetch that dependency package once again(sometimes there are yet another dependency package required for installing your dependency package.So it becomes a tedious job). Continue reading

Creating Logical Volume on Unix/Linux

What is a Logical Volume Manager?

LVM is a method of allocating hard drive space into logical volumes that can be easily resized instead of partitions. With LVM, the hard drive or set of hard drives is allocated to one or more physical volumes. A physical volume can not span over more than one drive.The physical volumes are combined into logical volume groups, with the exception of the /boot/ partition. The /boot/ partition can not be on a logical volume group because the boot loader can not read it. If the root / partition is on a logical volume, create a separate /boot/ partition which is not a part of a volume group.

Since a physical volume can not span over more than one drive, to span over more than one drive, create one or more physical volumes per drive. The logical volume group is divided into logical volumes, which are assigned mount points such as /home and / and file system types such as ext3. When “partitions” reach their full capacity, free space from the logical volume group can be added to the logical volume to increase the size of the partition. When a new hard drive is added to the system, it can be added to the logical volume group, and the logical volumes that are the partitions can be expanded. Continue reading

Creating a partition on Linux

What is a Partition?

A partition is a logical division on a hard disk drive (HDD).

HDDs are the main storage device on most computers. Storage refers to devices or media that can retain data for relatively long periods of time, in contrast with memory, whose contents can be accessed (i.e., read and written to) at extremely high speeds but which are retained only temporarily (i.e., while in use or only as long as the power supply remains on).

The desired number and sizes of partitions can be easily created on a HDD during the installation of an operating system. New partitions can also be created after the operating system has been installed by using available free space (i.e., space that has not yet been partitioned) or by erasing existing partitions to create free space.

Continue reading