tailieunhanh - Oracle Database Administration for Microsoft SQL Server DBAs part 30

Oracle Database Administration for Microsoft SQL Server DBAs part 30 takes the administration topics with which the SQL Server DBA is familiar, translates them into Oracle terms, and then expands on Oracle functionality. Definitions and comparative terms run throughout the book so the SQL Server DBA can easily leverage existing knowledge. This Oracle Press guide also expands on some of the features in Oracle that do not match up directly with SQL Server, and looks at other processes often performed on an Oracle database that would not typically be a standard practice in SQL Server environments | This page intentionally left blank CHAPTER 10 High-Availability Architecture 274 Oracle Database Administration for Microsoft SQL Server DBAs liminating single points of failure and decreasing planned or unplanned downtime make a database environment more highly available. Chapter 6 discussed failures and recovery options to help decrease some unplanned downtime. When planning high-availability solutions and failover capabilities the failures also need to be considered. This includes not only unplanned outages but planned ones as well. Planning for unexpected failures is not an easy task but with an understanding of database systems you can have an idea of what might happen. So what are some of the unexpected failures Hardware failures from servers memory storage network and other components of the server can be included in this area. Another area is data failures which can come from changes and could be a result of another failure such as storage. Planned outages are a little more obvious. Patching upgrading and making configuration changes fall into this category. Some patches and upgrades can be applied with minimal or no downtime. As a DBA understanding the options that are available and the purposes that they serve to develop a high-availability system is critical. The options and components have pros and cons whether you are working with an Oracle or a SQL Server system. You ll need to gather requirements explore the available options and then architect a solution for your particular database system. Usually you ll use a combination of components and options to build a successful high-availability design and implementation. In this chapter you ll learn about the high-availability options available for an Oracle system. This will help you choose the most suitable solution for your database system. Options for High Availability Oracle and SQL Server have different components and features for ensuring a database system is highly available. Table 10-1 lists the .