crystal reports barcode font not printing Data Center Disasters in Font

Generate QR-Code in Font Data Center Disasters

Data Center Disasters
Making Quick Response Code In None
Using Barcode creator for Font Control to generate, create QR Code image in Font applications.
www.OnBarcode.com
Print UPC - 13 In None
Using Barcode creation for Font Control to generate, create EAN13 image in Font applications.
www.OnBarcode.com
Data center disasters could range from a tornado to a fire to a terrorist attack. I discussed the Oracle Data Guard feature, which makes use of standby databases, in 15. Standby databases provide good protection against a data center disaster. Your business will continue to run without any interruption, because all the changes made to your operational database are sent to a duplicate standby database over the network. In a disaster recovery situation, you just turn the duplicate database into your main production database, with almost no disruption and no loss of data. You can also use Oracle s Advanced Replication feature, whereby you maintain a distributed database system so a remote distributed database can take over from the primary production system if it suffers a total failure.
Drawing EAN / UCC - 14 In None
Using Barcode generation for Font Control to generate, create UCC - 12 image in Font applications.
www.OnBarcode.com
Code 128C Maker In None
Using Barcode generator for Font Control to generate, create Code 128 Code Set B image in Font applications.
www.OnBarcode.com
Human Error
Encode UPC-A Supplement 2 In None
Using Barcode printer for Font Control to generate, create GTIN - 12 image in Font applications.
www.OnBarcode.com
Barcode Generation In None
Using Barcode creation for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
People can and do make mistakes. DBAs or system administrators can make critical errors that might put their databases in jeopardy. For example, you could accidentally run the wrong batch job, producing data that is meaningless or wrong. If you have entered incorrect data into a table or deleted some data in error, you have several ways to get out of the jam. You can use Oracle s Flashback Query feature to query old data and replace the lost or wrongly entered data without taking the database offline. 6 dealt with various Flashback features that use undo data. In this chapter, I discuss the Flashback Database and Flashback Drop features, which enable you to perform a database or table recovery without restoring data files. You can also use Oracle s LogMiner tool to read your redo logs and undo changes to the database. You can use Data Pump Export and Import to replace the affected tables, but you may lose some data in the process. Or, you can perform a point-in-time recovery (PITR) to recover the database or a tablespace to a point in time before the problem occurred. However, the new Flashback features are a better alternative in most cases, as you ll see later in this chapter.
PDF-417 2d Barcode Drawer In None
Using Barcode encoder for Font Control to generate, create PDF-417 2d barcode image in Font applications.
www.OnBarcode.com
ISSN Generation In None
Using Barcode drawer for Font Control to generate, create International Standard Serial Number image in Font applications.
www.OnBarcode.com
CHAPTER 16 DATABASE RECOVERY
QR Code Generation In VS .NET
Using Barcode creator for VS .NET Control to generate, create QR Code JIS X 0510 image in .NET framework applications.
www.OnBarcode.com
QR Code JIS X 0510 Generator In None
Using Barcode creation for Office Excel Control to generate, create QR Code JIS X 0510 image in Excel applications.
www.OnBarcode.com
Media Failures
EAN128 Drawer In VS .NET
Using Barcode creator for .NET framework Control to generate, create UCC.EAN - 128 image in Visual Studio .NET applications.
www.OnBarcode.com
Barcode Creator In Java
Using Barcode printer for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
The most serious recovery issues are those related to media problems. Damage to disks that prevent them from being read from or written to is the most serious scenario, and you ll have to depend on your backup copies of the database and log files to make the database current without any permanent loss of data. If your data files or control files are on the inaccessible media, you ll most likely end up doing a recovery. In some situations, you may perform a recovery even if there s no media damage for instance, when there s a serious case of user error. If you have to restore a backed-up data file or you take a file offline using the OFFLINE IMMEDIATE option, you ll need to perform a media recovery. Two factors are critical when disasters occur: the amount of data that becomes unavailable and needs to be replaced from backups, and the amount of time it might take to replace the data.
Print EAN-13 In .NET Framework
Using Barcode drawer for ASP.NET Control to generate, create GS1 - 13 image in ASP.NET applications.
www.OnBarcode.com
QR Code 2d Barcode Decoder In .NET Framework
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
The Oracle Recovery Process
Code-39 Decoder In VB.NET
Using Barcode scanner for .NET framework Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
QR Code Printer In C#.NET
Using Barcode maker for VS .NET Control to generate, create Quick Response Code image in Visual Studio .NET applications.
www.OnBarcode.com
You can broadly divide Oracle database recoveries into crash and instance recoveries on one hand and media recoveries on the other. Let s clarify the differences between these two types of recoveries.
Data Matrix Generator In VS .NET
Using Barcode generation for ASP.NET Control to generate, create DataMatrix image in ASP.NET applications.
www.OnBarcode.com
UPC Symbol Printer In Java
Using Barcode encoder for Eclipse BIRT Control to generate, create UPC Symbol image in Eclipse BIRT applications.
www.OnBarcode.com
Crash and Instance Recovery
Code 128 Code Set B Generation In None
Using Barcode encoder for Excel Control to generate, create Code-128 image in Office Excel applications.
www.OnBarcode.com
EAN13 Maker In Objective-C
Using Barcode generator for iPhone Control to generate, create UPC - 13 image in iPhone applications.
www.OnBarcode.com
Oracle automatically performs crash recovery when a single instance suddenly fails, or when all instances of a multiple-instance Oracle Real Application Cluster (RAC) fail. Also, if you shut down your database with the SHUTDOWN ABORT command, Oracle has to perform a crash recovery. Instance recovery is very similar to crash recovery, but it applies to cases where a surviving instance recovers the failed instances in an RAC setup. The essential point about crash and instance recoveries is that you don t apply any backed-up data files or archived logs during recovery. Oracle uses only the current data files and online redo log files to bring the database up to date. Crash and instance recovery involves the following two-step procedure: 1. Roll-forward step: During this step, formally called cache recovery, the database applies the committed and uncommitted data in the current online redo log files to the current online data files. 2. Rollback step: During this step, formally called transaction recovery, the database removes the uncommitted transactions applied in the previous step, using the undo data in the undo segments. As you know, when the database suddenly crashes, not all the committed transactions will have been written to disk. If your database is large, and the redo log files are also large, it can take a long time for the roll-forward and rollback to complete. By using Oracle s Fast-Start Fault Recovery functionality, you can substantially reduce the downtime resulting from system-related outages. The roll-forward phase of a crash recovery uses the redo logs to see what changes need to be applied to disk. Redo application begins at a point in the redo logs known as the thread checkpoint redo byte address. This is the time when the last checkpoint was done before the crash. Because all the data in the buffers is written to disk during a checkpoint, only changes after this last checkpoint position will need to be recovered. Fast-Start Checkpointing is the frequent writing of the dirty database buffers in the cache to disk by the database writer (DBWn). Fast-Start Checkpointing is the basis of Oracle s Fast-Start Fault Recovery feature. You can minimize the time required for crash recovery by frequently advancing the checkpoint position. Oracle uses a two-pass technique to perform a recovery using the checkpoints. In the first pass, it determines which blocks in the redo logs need recovery, and in the second pass the database applies the required changes.
Copyright © OnBarcode.com . All rights reserved.