6 Configuring Data Protection Modes and Redo Transport Services

Chia sẻ: Nguyễn Lương Nghĩa | Ngày: | Loại File: PPT | Số trang:28

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Nội dung Text: 6 Configuring Data Protection Modes and Redo Transport Services

6 Configuring Data Protection Modes and Redo Transport Services Copyright © 2006, Oracle. All rights reserved.
Objectives After completing this lesson, you should be able to do the following: • Describe the data protection modes • Change the data protection mode of your configuration • Modify redo transport services to serve your needs 6-2 Copyright © 2006, Oracle. All rights reserved.
Data Protection Modes and Redo Transport Modes • A data protection mode requires a specific redo transport mode. • A redo transport mode alone does not define a data protection mode. 6-3 Copyright © 2006, Oracle. All rights reserved.
Defining the Redo Transport Mode Use the attributes of LOG_ARCHIVE_DEST_n: • ARCH and LGWR – Specify that either the archiver process or the log writer process is responsible for transmitting redo to the standby destination – ARCH is the default. • SYNC and ASYNC (LGWR only) – Specify that network I/O operations are to be performed synchronously or asynchronously when using LGWR – SYNC is the default. • AFFIRM and NOAFFIRM – Ensure that redo has been successfully written to disk on the standby destination – NOAFFIRM is the default. 6-4 Copyright © 2006, Oracle. All rights reserved.
6-5 Copyright © 2006, Oracle. All rights reserved.
Setting the Redo Transport Mode Click Edit to access the Edit Standby Database Properties page. 6-6 Copyright © 2006, Oracle. All rights reserved.
Setting the Redo Transport Mode Select the mode from the Log Transport Mode list. 6-7 Copyright © 2006, Oracle. All rights reserved.
Data Protection Modes • Three data protection modes: – Maximum protection – Maximum availability – Maximum performance • Help to balance data availability and system performance 6-8 Copyright © 2006, Oracle. All rights reserved.
Maximum Protection • Enables zero data loss • Redo data must be written to both the local online redo log and the standby redo log on at least one standby database. • Primary database shuts down if a fault prevents it from writing its redo stream to at least one remote standby redo log. • Configuration requirements: – Standby redo log files on at least one standby database – SYNC, LGWR, and AFFIRM attributes for at least one standby database 6-9 Copyright © 2006, Oracle. All rights reserved.
Maximum Availability • Enables zero data loss • Provides the highest possible level of data protection without compromising the availability of the primary database • Redo data must be written to both the local online redo log and the standby redo log on at least one standby database. • Primary database does not shut down if a fault prevents it from writing its redo stream. • Configuration requirements: – Standby redo log files on at least one standby database – SYNC, LGWR, and AFFIRM attributes for at least one standby database 6 - 10 Copyright © 2006, Oracle. All rights reserved.
Maximum Performance • Default level of data protection • Provides the highest possible level of data protection without affecting the performance of the primary database • Transactions can commit as soon as the redo data is written to the local online redo log. • Redo stream is written asynchronously with respect to the commitment of the transactions that create the redo data. 6 - 11 Copyright © 2006, Oracle. All rights reserved.
Setting the Data Protection Mode Click the Protection Mode link. 6 - 12 Copyright © 2006, Oracle. All rights reserved.
Setting the Data Protection Mode 6 - 13 Copyright © 2006, Oracle. All rights reserved.
Setting the Data Protection Mode by Using the CLI 1. Configure standby redo logs. 2. Set the LogXptMode property (if necessary). 3. Set the data protection mode. DGMGRL> EDIT DATABASE 'site1_edrsr8p1' SET PROPERTY 'LogXptMode'='SYNC'; DGMGRL> EDIT CONFIGURATION SET PROTECTION MODE AS MAXAVAILABILITY; 6 - 14 Copyright © 2006, Oracle. All rights reserved.
Setting the Protection Mode by Using SQL • You must set attributes to support the type of protection desired. • Issue the ALTER DATABASE statement on the primary database: ALTER DATABASE SET STANDBY TO MAXIMIZE PROTECTION; 6 - 15 Copyright © 2006, Oracle. All rights reserved.
Delaying the Application of Redo Delaying the application of redo helps safeguard against: • Data corruption • User errors Oracle Net Delayed application Production Standby database database 6 - 16 Copyright © 2006, Oracle. All rights reserved.
Using Enterprise Manager to Delay the Application of Redo Specify the delay in minutes. 6 - 17 Copyright © 2006, Oracle. All rights reserved.
Setting LOG_ARCHIVE_DEST_n to Delay the Application of Redo Use the attributes of LOG_ARCHIVE_DEST_n to control the application of redo: • DELAY: number of minutes to delay application of redo (default: 30 minutes) 6 - 18 Copyright © 2006, Oracle. All rights reserved.
Using Flashback Database Instead of Apply Delay Standby1 No delay Primary Standby2 database 4-hour delay Standby3 8-hour delay Primary Standby database 6 - 19 Copyright © 2006, Oracle. All rights reserved.
Additional Attributes That Affect Redo Transport Services • ALTERNATE • DEPENDENCY • MAX_FAILURE • NET_TIMEOUT • REOPEN 6 - 20 Copyright © 2006, Oracle. All rights reserved.