Tasks of a Database Administrator
Apart from the normal health-checks and monitoring the databases on a regular basis, the following tasks present a prioritized approach for designing, implementing, and maintaining an Oracle Database, these tasks are discussed below:
Task 1: Evaluate the Database Server Hardware
Evaluate how Oracle Database and its applications can best use the available computer resources. This evaluation should reveal the following information:
Task 2: Install the Oracle Database Software
As the database administrator, you install the Oracle Database server software and any front-end tools and database applications that access the database. In some distributed processing installations, the database is controlled by a central computer (database server) and the database tools and applications are executed on remote computers (clients). In this case, you must also install the Oracle Net components necessary to connect the remote machines to the computer that executes Oracle Database.
Task 3: Plan the Database
As the database administrator, you must plan:
It is important to plan how the logical storage structure of the database will affect system performance and various database management operations. For example, before creating any tablespaces for your database, you should know how many datafiles will make up the tablespace, what type of information will be stored in each tablespace, and on which disk drives the datafiles will be physically stored. When planning the overall logical storage of the database structure, take into account the effects that this structure will have when the database is actually created and running. Consider how the logical storage structure of the database will affect:
Plan the relational design of the database objects and the storage characteristics for each of these objects. By planning the relationship between each object and its physical storage before creating it, you can directly affect the performance of the database as a unit. Be sure to plan for the growth of the database.
In distributed database environments, this planning stage is extremely important. The physical location of frequently accessed data dramatically affects application performance.
During the planning stage, develop a backup strategy for the database. You can alter the logical storage structure or design of the database to improve backup efficiency.
It is beyond the scope of this book to discuss relational and distributed database design. If you are not familiar with such design issues, please refer to accepted industry-standard documentation.
Task 4: Create and Open the Database
After you complete the database design, you can create the database and open it for normal use. You can create a database at installation time, using the Database Configuration Assistant, or you can supply your own scripts for creating a database.
Task 5: Back Up the Database
After you create the database structure, carry out the backup strategy you planned for the database. Create any additional redo log files, take the first full database backup (online or offline), and schedule future database backups at regular intervals.
Task 6: Enroll System Users
After you back up the database structure, you can enroll the users of the database in accordance with your Oracle license agreement, and grant appropriate privileges and roles to these users.
Task 7: Implement the Database Design
After you create and start the database, and enroll the system users, you can implement the planned logical structure database by creating all necessary tablespaces. When you have finished creating tablespaces, you can create the database objects.
Task 8: Back Up the Fully Functional Database
When the database is fully implemented, again back up the database. In addition to regularly scheduled backups, you should always back up your database immediately after implementing changes to the database structure.
Task 9: Tune Database Performance
Optimizing the performance of the database is one of your ongoing responsibilities as a DBA. Oracle Database provides a database resource management feature that helps you to control the allocation of resources among various user groups.
Task 10: Download and Install Patches
After installation and on a regular basis, download and install patches. Patches are available as single interim patches and as patchsets (or patch releases). Interim patches address individual software bugs and may or may not be needed at your installation. Patch releases are collections of bug fixes that are applicable for all customers. Patch releases have release numbers. For example, if you installed Oracle Database 10.2.0.0, the first patch release will have a release number of 10.2.0.1.
Task 11: Roll Out to Additional Hosts
After you have an Oracle Database installation properly configured, tuned, patched, and tested, you may want to roll that exact installation out to other hosts. Reasons to do this include the following:
Instead of installing, tuning, and patching on each additional host, you can clone your tested Oracle Database installation to other hosts, saving time and eliminating inconsistencies. There are two types of cloning available to you:
You can use the Enterprise Manager Clone Database tool to clone an Oracle database instance to an existing Oracle home.
Apart from the normal health-checks and monitoring the databases on a regular basis, the following tasks present a prioritized approach for designing, implementing, and maintaining an Oracle Database, these tasks are discussed below:
Task 1: Evaluate the Database Server Hardware
Evaluate how Oracle Database and its applications can best use the available computer resources. This evaluation should reveal the following information:
- How many disk drives are available to the Oracle products
- How many, if any, dedicated tape drives are available to Oracle products
- How much memory is available to the instances of Oracle Database you will run (see your system configuration documentation)
Task 2: Install the Oracle Database Software
As the database administrator, you install the Oracle Database server software and any front-end tools and database applications that access the database. In some distributed processing installations, the database is controlled by a central computer (database server) and the database tools and applications are executed on remote computers (clients). In this case, you must also install the Oracle Net components necessary to connect the remote machines to the computer that executes Oracle Database.
Task 3: Plan the Database
As the database administrator, you must plan:
- The logical storage structure of the database
- The overall database design
- A backup strategy for the database
It is important to plan how the logical storage structure of the database will affect system performance and various database management operations. For example, before creating any tablespaces for your database, you should know how many datafiles will make up the tablespace, what type of information will be stored in each tablespace, and on which disk drives the datafiles will be physically stored. When planning the overall logical storage of the database structure, take into account the effects that this structure will have when the database is actually created and running. Consider how the logical storage structure of the database will affect:
- The performance of the computer executing running Oracle Database
- The performance of the database during data access operations
- The efficiency of backup and recovery procedures for the database
Plan the relational design of the database objects and the storage characteristics for each of these objects. By planning the relationship between each object and its physical storage before creating it, you can directly affect the performance of the database as a unit. Be sure to plan for the growth of the database.
In distributed database environments, this planning stage is extremely important. The physical location of frequently accessed data dramatically affects application performance.
During the planning stage, develop a backup strategy for the database. You can alter the logical storage structure or design of the database to improve backup efficiency.
It is beyond the scope of this book to discuss relational and distributed database design. If you are not familiar with such design issues, please refer to accepted industry-standard documentation.
Task 4: Create and Open the Database
After you complete the database design, you can create the database and open it for normal use. You can create a database at installation time, using the Database Configuration Assistant, or you can supply your own scripts for creating a database.
Task 5: Back Up the Database
After you create the database structure, carry out the backup strategy you planned for the database. Create any additional redo log files, take the first full database backup (online or offline), and schedule future database backups at regular intervals.
Task 6: Enroll System Users
After you back up the database structure, you can enroll the users of the database in accordance with your Oracle license agreement, and grant appropriate privileges and roles to these users.
Task 7: Implement the Database Design
After you create and start the database, and enroll the system users, you can implement the planned logical structure database by creating all necessary tablespaces. When you have finished creating tablespaces, you can create the database objects.
Task 8: Back Up the Fully Functional Database
When the database is fully implemented, again back up the database. In addition to regularly scheduled backups, you should always back up your database immediately after implementing changes to the database structure.
Task 9: Tune Database Performance
Optimizing the performance of the database is one of your ongoing responsibilities as a DBA. Oracle Database provides a database resource management feature that helps you to control the allocation of resources among various user groups.
Task 10: Download and Install Patches
After installation and on a regular basis, download and install patches. Patches are available as single interim patches and as patchsets (or patch releases). Interim patches address individual software bugs and may or may not be needed at your installation. Patch releases are collections of bug fixes that are applicable for all customers. Patch releases have release numbers. For example, if you installed Oracle Database 10.2.0.0, the first patch release will have a release number of 10.2.0.1.
Task 11: Roll Out to Additional Hosts
After you have an Oracle Database installation properly configured, tuned, patched, and tested, you may want to roll that exact installation out to other hosts. Reasons to do this include the following:
- You have multiple production database systems.
- You want to create development and test systems that are identical to your production system.
Instead of installing, tuning, and patching on each additional host, you can clone your tested Oracle Database installation to other hosts, saving time and eliminating inconsistencies. There are two types of cloning available to you:
- Cloning an Oracle home—Just the configured and patched binaries from the Oracle home directory and subdirectories are copied to the destination host and "fixed" to match the new environment. You can then start an instance with this cloned home and create a database.
- Cloning a database—The tuned database, including database files, initialization parameters, and so on, are cloned to an existing Oracle home (possibly a cloned home).
You can use the Enterprise Manager Clone Database tool to clone an Oracle database instance to an existing Oracle home.
No comments:
Post a Comment