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 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 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 - 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 - 11 Copyright © 2006, Oracle All rights reserved Setting the Data Protection Mode by Using the CLI Configure standby redo logs Set the LogXptMode property (if necessary) Set the data protection mode DGMGRL> EDIT DATABASE 'site1_edrsr8p1' SET PROPERTY 'LogXptMode'='SYNC'; DGMGRL> EDIT CONFIGURATION SET PROTECTION MODE AS MAXAVAILABILITY; - 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; - 15 Copyright © 2006, Oracle All rights reserved Delaying the Application of Redo Production database - 16 Oracle Net Delaying the application of redo helps safeguard against: • Data corruption • User errors Delayed application Copyright © 2006, Oracle All rights reserved Standby database Using Enterprise Manager to Delay the Application of Redo Specify the delay in minutes - 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) - 18 Copyright © 2006, Oracle All rights reserved Using Flashback Database Instead of Apply Delay Standby1 No delay Primary database Standby2 4-hour delay Standby3 8-hour delay Primary database - 19 Standby Copyright © 2006, Oracle All rights reserved Additional Attributes That Affect Redo Transport Services • • • • • - 20 ALTERNATE DEPENDENCY MAX_FAILURE NET_TIMEOUT REOPEN Copyright © 2006, Oracle All rights reserved Using the ALTERNATE Attribute • Can specify one alternate destination for the LOG_ARCHIVE_DEST_n parameter • Allow a failed destination to change destinations – Disk full: switch to new disk – Oracle Net link fails: switch to new network link • Require REOPEN=0 or MAX_FAILURE • Enabled with LOG_ARCHIVE_DEST_STATE_n log_archive_dest_3='SERVICE=stby1_path1 REOPEN=0 ALTERNATE=LOG_ARCHIVE_DEST_4' log_archive_dest_4='SERVICE=stby1_path2 REOPEN=0 OPTIONAL' log_archive_dest_state_3=ENABLE log_archive_dest_state_4=ALTERNATE - 21 Copyright © 2006, Oracle All rights reserved Using the MAX_FAILURE Attribute MAX_FAILURE[=count] • Number of times redo transport services attempts to reestablish communication • Requires REOPEN • No default count log_archive_dest_3='SERVICE=o10g1 LGWR MAX_FAILURE=30 REOPEN' - 22 Copyright © 2006, Oracle All rights reserved Using the NET_TIMEOUT Attribute • Enables the LGWR process to avoid a network timeout issue • Valid with SYNC or ASYNC destinations • Value supplied is the number of seconds to wait • Range of values for NET_TIMEOUT: 15 to 1200 • Default: 180 • Use caution in maximum protection mode log_archive_dest_2='SERVICE=o10g2 LGWR SYNC NET_TIMEOUT=30' - 23 Copyright © 2006, Oracle All rights reserved Using the REOPEN Attribute • REOPEN[=seconds] – Minimum number of seconds to wait before retrying a failed destination at log switch – Failures can be network failures, quota exceptions, disk full, and so on – Default: 300 seconds (5 minutes) • REOPEN=0 – Failed destinations remain disabled until: — — — Manually reenabled ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_n=ENABLE issued Instance restart – Required when using ALTERNATE destinations with MAX_FAILURE=0 attributes - 24 Copyright © 2006, Oracle All rights reserved Optimized Asynchronous Redo Transmission Primary database transactions MRP or LSP Standby database (MRP only) LNSn RFS Oracle Net LGWR Online redo logs FAL Backup Reports ARC0 ARC1 ARC2 Archived redo logs - 25 Archived redo logs Copyright © 2006, Oracle All rights reserved Enabling Multiple Connections for Remote Archival of Redo The following conditions must be met to enable this feature: • Remote archiving is performed to disk • LOG_ARCHIVE_LOCAL_FIRST must be set to TRUE (default) LOG_ARCHIVE_DEST_3= 'SERVICE=detroit MAX_CONNECTIONS=5' - 26 Copyright © 2006, Oracle All rights reserved Summary In this lesson, you should have learned how to: • Describe the data protection modes • Change the data protection mode of your configuration • Modify redo transport services to suit your needs • Delay the application of redo • Use additional transport services attributes - 27 Copyright © 2006, Oracle All rights reserved Practice 6: Overview This practice covers the following topics: • Changing the data protection mode • Delaying the application of redo - 28 Copyright © 2006, Oracle All rights reserved [...]... MAX_CONNECTIONS=5' 6 - 26 Copyright © 20 06, Oracle All rights reserved Summary In this lesson, you should have learned how to: • Describe the data protection modes • Change the data protection mode of your configuration • Modify redo transport services to suit your needs • Delay the application of redo • Use additional transport services attributes 6 - 27 Copyright © 20 06, Oracle All rights reserved Practice 6: ... application of redo: • DELAY: number of minutes to delay application of redo (default: 30 minutes) 6 - 18 Copyright © 20 06, Oracle All rights reserved Using Flashback Database Instead of Apply Delay Standby1 No delay Primary database Standby2 4-hour delay Standby3 8-hour delay Primary database 6 - 19 Standby Copyright © 20 06, Oracle All rights reserved Additional Attributes That Affect Redo Transport Services. ..Setting the Data Protection Mode Click the Protection Mode link 6 - 12 Copyright © 20 06, Oracle All rights reserved Setting the Data Protection Mode 6 - 13 Copyright © 20 06, 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 PROTECTION MODE AS MAXAVAILABILITY; 6 - 14 Copyright © 20 06, 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 © 20 06, Oracle All rights reserved Delaying the Application of Redo. .. attributes 6 - 24 Copyright © 20 06, Oracle All rights reserved Optimized Asynchronous Redo Transmission Primary database transactions MRP or LSP Standby database (MRP only) LNSn RFS Oracle Net LGWR Online redo logs FAL Backup Reports ARC0 ARC1 ARC2 Archived redo logs 6 - 25 Archived redo logs Copyright © 20 06, Oracle All rights reserved Enabling Multiple Connections for Remote Archival of Redo The... Production database 6 - 16 Oracle Net Delaying the application of redo helps safeguard against: • Data corruption • User errors Delayed application Copyright © 20 06, Oracle All rights reserved Standby database Using Enterprise Manager to Delay the Application of Redo Specify the delay in minutes 6 - 17 Copyright © 20 06, Oracle All rights reserved Setting LOG_ARCHIVE_DEST_n to Delay the Application of Redo. .. log_archive_dest_state_3=ENABLE log_archive_dest_state_4=ALTERNATE 6 - 21 Copyright © 20 06, Oracle All rights reserved Using the MAX_FAILURE Attribute MAX_FAILURE[=count] • Number of times redo transport services attempts to reestablish communication • Requires REOPEN • No default count log_archive_dest_3='SERVICE=o10g1 LGWR MAX_FAILURE=30 REOPEN' 6 - 22 Copyright © 20 06, Oracle All rights reserved Using the NET_TIMEOUT... transport services attributes 6 - 27 Copyright © 20 06, Oracle All rights reserved Practice 6: Overview This practice covers the following topics: • Changing the data protection mode • Delaying the application of redo 6 - 28 Copyright © 20 06, Oracle All rights reserved ... Default: 180 • Use caution in maximum protection mode log_archive_dest_2='SERVICE=o10g2 LGWR SYNC NET_TIMEOUT=30' 6 - 23 Copyright © 20 06, Oracle All rights reserved Using the REOPEN Attribute • REOPEN[=seconds] – Minimum number of seconds to wait before retrying a failed destination at log switch – Failures can be network failures, quota exceptions, disk full, and so on – Default: 300 seconds (5 minutes)... Standby3 8-hour delay Primary database 6 - 19 Standby Copyright © 20 06, Oracle All rights reserved Additional Attributes That Affect Redo Transport Services • • • • • 6 - 20 ALTERNATE DEPENDENCY MAX_FAILURE NET_TIMEOUT REOPEN Copyright © 20 06, Oracle All rights reserved Using the ALTERNATE Attribute • Can specify one alternate destination for the LOG_ARCHIVE_DEST_n parameter • Allow a failed destination ... 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 © 20 06, Oracle... the data protection modes • Change the data protection mode of your configuration • Modify redo transport services to serve your needs 6- 2 Copyright © 20 06, Oracle All rights reserved Data Protection. .. 20 06, 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