You specify the location for LOG_ARCHIVE_DEST_n using the keywords explained in the following table: A local file system location or Oracle ASM disk group, LOG_ARCHIVE_DEST_n = 'LOCATION=/disk1/arc', LOG_ARCHIVE_DEST_n = 'LOCATION=+DGROUP1/orcl/arc_1', LOG_ARCHIVE_DEST_n = 'LOCATION=USE_DB_RECOVERY_FILE_DEST'. Displays information about the state of the various archive processes for an instance. If all databases in a distributed database operate in ARCHIVELOG mode, you can perform coordinated distributed database recovery. Whenever the database archives a redo log, it archives it to every destination specified by either set of parameters. NOARCHIVELOG mode protects a database from instance failure but not from media failure. Each archive destination has the following variable characteristics that determine its status: Valid/Invalid: indicates whether the disk location or service name information is specified and valid, Enabled/Disabled: indicates the availability state of the location and whether the database can use the destination, Active/Inactive: indicates whether there was a problem accessing the destination. The database can reuse logs only if at least one OPTIONAL destination succeeds. Before making any major change to a database, always back up the database to protect against any problems. Contains log history information such as which logs have been archived and the SCN range for each archived log. The following table summarizes the archive destination alternatives, which are further described in the sections that follow. The dynamic performance (V$) views, listed in "Viewing Information About the Archived Redo Log", provide all needed archive information. Ensure that the database is either mounted or open. The archived redo log destination is D:\oracle\oradata\IDDB2\archive.
ALTERNATE indicates that the destination is an alternate. Oracle Database Backup and Recovery User's Guide for information about the Fast Recovery Area. The database control file indicates that filled groups are not required to be archived. You cannot recover transactions subsequent to that backup. Valid values for n are 1 to 2 if you are using duplexing, or 1 to 31 if you are multiplexing. Oracle Real Application Clusters Administration and Deployment Guide, Edit the initialization parameter file to include the initialization parameters that specify the destinations for the archived redo log files (see. You can see the relationship between the LOG_ARCHIVE_DEST_n and LOG_ARCHIVE_MIN_SUCCEED_DEST initialization parameters most easily through sample scenarios. When you archive to multiple destinations, a copy of each filled redo log file is written to each destination. The LOG_ARCHIVE_DEST_STATE_n (where n is an integer from 1 to 31) initialization parameter lets you control the availability state of the specified destination (n). Table 12-2 shows the possible values for LOG_ARCHIVE_MIN_SUCCEED_DEST=n. Refer to the following sections for detailed instructions: If you are automatically archiving, you can use the following The REOPEN attempt either succeeds or fails. The following example makes LOG_ARCHIVE_DEST_4 an alternate for LOG_ARCHIVE_DEST_3: The two modes of transmitting archived logs to their destination are normal archiving transmission and standby transmission mode. The default value for n is 300 seconds. To change the archiving mode, you must be connected to the database with administrator privileges (AS SYSDBA). There is no ACTIVE status. To avoid any run-time overhead of starting additional ARCn processes: Set the LOG_ARCHIVE_MAX_PROCESSES initialization parameter to specify that up to 30 ARCn processes be started at instance startup. If you use a recovery catalog, the RC_BACKUP_REDOLOG contains similar information. Whenever the database archives a redo log, it archives it to every destination specified by either set of parameters. Changing the database archiving mode updates the control file. for Enterprise Edition users. examples. Only the most recent changes made to the database, which are stored in the online redo log groups, are available for instance recovery. Start a new instance and mount, but do not open, the database.
See Oracle Database Backup and Recovery User's Guide for details about the Fast Recovery Area. However, you can use the ALTER SYSTEM command to dynamically add or change archive destinations after your database is running. To enable or disable archiving, the database must be mounted but not open. You must be connected to an open Oracle database as SYSOPER, or SYSDBA. When you run a database in ARCHIVELOG mode, you enable the archiving of the redo log. The default value is 1. To specify a maximum of two locations, use the LOG_ARCHIVE_DEST parameter to specify a primary archive destination and the LOG_ARCHIVE_DUPLEX_DEST to specify an optional secondary archive destination. If you are duplexing the archived logs, you can establish which destinations are mandatory or optional by using the LOG_ARCHIVE_DEST and LOG_ARCHIVE_DUPLEX_DEST parameters. n is an integer from 1 to 31. If you want to archive to only a single destination, then specify that destination using the LOG_ARCHIVE_DEST initialization parameter. This will be your final backup of the database in NOARCHIVELOG mode and can be used if something goes wrong during the change to ARCHIVELOG mode. ALTERNATE indicates that the destination is an alternate. Before you can archive redo logs, you must determine the destination to which you will archive, and familiarize yourself with the various destination states. For information about specifying archive destinations, see your platform-specific Oracle Database documentation. The database control file indicates that a group of filled redo log files cannot be reused by LGWR until the group is archived. After creating the database, decide whether to change the initial archiving mode. A filled group becomes available for archiving immediately after a redo log switch occurs. file. The VALID and ENABLED states are not changed. If you specify SERVICE, supply a net service name that Oracle Net can resolve to a connect descriptor for a standby database. 
Then open the database for normal operations. Describes the current instance, all archive destinations, and the current value, mode, and status of these destinations. When the database is running in ARCHIVELOG mode, the log writer process (LGWR) cannot reuse and hence overwrite a redo log group until it has been archived. For example, enter: The database requires the specification of resetlogs ID (%r) when you include the LOG_ARCHIVE_FORMAT parameter. If its parent destination fails, the availability state of the alternate becomes ENABLE. The availability state of an alternate destination is DEFER. The oldest filled redo log group has a sequence number of 11160. If you use a recovery catalog, the. command to override the destination specified by the LOG_ARCHIVE_DEST. If you are using ARCHIVELOG but have disabled automatic archiving, the last three lines might look like: If you are using NOARCHIVELOG mode, the "next log sequence to archive" line is suppressed. Scripting on this page enhances content navigation, but does not change the content in any way. It is good practice to move archived redo log files and corresponding database backups from the local disk to permanent offline storage media such as tape. Background processes always write to a trace file when appropriate. The database uses the Fast Recovery Area to store and automatically manage disk space for a variety of files related to backup and recovery. To restore a database operating in NOARCHIVELOG mode, you can use only whole database backups taken while the database is closed. The current redo log file has a sequence number of 11163. Displays all redo log groups for the database and indicates which need to be archived. file dynamically. Change the database archiving mode. Oracle Data Guard Concepts and Administration, Oracle Database Net Services Administrator's Guide for information about connecting to a remote database using a service name. You set the initial archiving mode as part of database creation in the CREATE DATABASE statement. 
Displays information about redo log files. Requests a display that shows the range of redo log files to be archived, the current log file group's sequence number, and the current archive destination (specified by either the optional command text or by the initialization parameter LOG_ARCHIVE_DEST). The following rules apply: Any destination declared by LOG_ARCHIVE_DEST is mandatory. When you run your database in NOARCHIVELOG mode, you disable the archiving of the redo log. If you keep archived logs available, you can use a backup taken while the database is open and in normal system use. Get information about the history of a database using the LogMiner utility. SYSTEM command as shown below. You can set the archiving mode for your database and adjust the number of archiver processes. Several dynamic performance views contain useful information about archived redo log files, as summarized in the following table. Specifying %r causes the database to capture the resetlogs ID in the archived redo log file name. The LOG_ARCHIVE_DEST_STATE_n (where n is an integer from 1 to 31) initialization parameter lets you control the availability state of the specified destination (n). SQL*Plus User's Guide and Reference for more information on the ARCHIVE LOG LIST command. You can also set the DB_RECOVERY_FILE_DEST initialization parameter to a disk group destination. For example, the following query displays which redo log group requires archiving: To see the current archiving mode, query the V$DATABASE view: Oracle Database Reference for detailed descriptions of dynamic performance views.
The background process ARCn automates archiving operations when automatic archiving is enabled. Several combinations of these characteristics are possible. You must ensure that there is sufficient disk space at all times for archive log destinations. A value of 0 is the same as turning off the REOPEN attribute; ARCn will not attempt to archive after a failure. If it is, ARCn retries the log copy. Oracle Database Net Services Administrator's Guide for a discussion of net service names and connect descriptors. The following example shows a setting of LOG_ARCHIVE_FORMAT: This setting will generate archived logs as follows for thread 1; log sequence numbers 100, 101, and 102; resetlogs ID 509210197. Standby transmission involves transmitting files through a network to either a local or remote standby database. Figure 12-1 Redo Log File Use in ARCHIVELOG Mode. DL. Typically, you determine archive log destinations during database planning, and you set the initialization parameters for archive destinations during database installation. If you want to archive to multiple destinations, then you can choose to archive to two or more locations using the LOG_ARCHIVE_DEST_n initialization parameters, or to archive only to a primary and secondary destination using the LOG_ARCHIVE_DEST and LOG_ARCHIVE_DUPLEX_DEST initialization parameters. Temporarily Changing the Destination In Example 17-3, archive log files are generated with ARCHIVELOG mode enabled, DB_RECOVERY_FILE_DEST set to the +FRA disk group, and ORCL is the value of the DB_UNIQUE_NAME parameter. The log sequence increments every time the Log Writer begins to write to another redo log file group; it does not indicate the number of logs being used. Oracle Database Reference for additional information about the initialization parameters used to control the archiving of redo logs. Usually, you can use the default of NOARCHIVELOG mode at database creation because there is no need to archive the redo information generated by that process. SQL*Plus. When you archive to multiple destinations, a copy of each filled redo log file is written to each destination. For example, the following statement archives all unarchived redo log files: When you use manual archiving mode, you cannot specify any standby databases in the archiving destinations. You can check the alert log for a disk full message. Any destination changes that you make take effect at the next log switch (automatic or manual). For example, if you are multiplexing your redo log, and if group 1 contains identical member files a_log1 and b_log1, then the archiver process (ARCn) will archive one of these member files. If you specify ARCHIVELOG mode, you must have initialization parameters set that specify the destinations for the archived redo log files (see "Setting Initialization Parameters for Archive Destinations"). Contains information about any backups of archived logs. It includes the redo entries and the unique log sequence number of the identical member of the redo log group. The LOG_ARCHIVE_MIN_SUCCEED_DEST value cannot be greater than the number of destinations, nor can it be greater than the number of MANDATORY destinations plus the number of OPTIONAL local destinations. You can also move your mouse over each individual icon to see only the screenshot Remote archival through Oracle Net service name. When using the REOPEN keyword, note the following: ARCn reopens a destination only when starting an archive operation from the beginning of the log file, never during a current operation. There are additional keywords that can be specified with this initialization parameter that are not discussed in this book. You can keep a standby database current with its original database by continuously applying the original archived redo log files to the standby. Perform the following steps to set the destination for archived redo logs using the LOG_ARCHIVE_DEST_n initialization parameter: Set the LOG_ARCHIVE_DEST_n initialization parameter to specify from one to 31 archiving locations. For example, setting LOG_ARCHIVE_TRACE=12 will generate trace level 8 and 4 output. To obtain the current status and other information about each destination for an instance, query the V$ARCHIVE_DEST view. Refer to the following section for detailed instructions: You can also change the value in the initialization parameter If this happens, the database writes an error message to the alert log. Contains log history information such as which logs have been archived and the SCN range for each archived log. REOPEN=n sets the minimum number of seconds before ARCn should try to reopen a failed destination. The archiving of filled groups has these advantages: A database backup, together with online and archived redo log files, guarantees that you can recover all committed transactions in the event of an operating system or disk failure. To change the archiving mode of the database, use the ALTER DATABASE statement with the ARCHIVELOG or NOARCHIVELOG clause. See Oracle Database Backup and Recovery User's Guide for more information about this method of recovery. The database can reuse log files only if all of the OPTIONAL destinations succeed. The LOG_ARCHIVE_MAX_PROCESSES parameter is dynamic, so you can change it using the ALTER SYSTEM statement. See Oracle Database Backup and Recovery User's Guide for details about the Fast Recovery Area. You can display information about the archived redo log using dynamic performance views or the ARCHIVE LOG LIST command. It increases or decreases the current number of running ARCn processes to six. For example, enter: Set the LOG_ARCHIVE_FORMAT initialization parameter as described in step 2 for method 1. The SQL*Plus command ARCHIVE LOG LIST displays archiving information for the connected instance. Oracle Data Guard Concepts and Administration for information about using the LOG_ARCHIVE_DEST_n initialization parameter for specifying a standby destination. ENABLE indicates that the database can use the destination. Archive destinations 11 to 31 are available for remote locations only. When destinations are specified in this manner, the archive log file names are created in default subdirectories with unique names. ALTERNATE cannot be specified for destinations LOG_ARCHIVE_DEST_11 to LOG_ARCHIVE_DEST_31.
Note: LOG_ARCHIVE_DEST The identical resetlogs ID indicates that the files are all from the same database incarnation: The LOG_ARCHIVE_FORMAT initialization parameter is ignored in some cases. Expand This module describes how you can change the destination for ERROR: The value is greater than the number of destinations. performing these steps. You cannot change the mode from ARCHIVELOG to NOARCHIVELOG if any data files need media recovery. Oracle Database lets you save filled groups of redo log files to one or more offline destinations, known collectively as the archived redo log. In standby transmission mode, the archiving destination is either a local or remote standby database. Perform the following steps the use method 2: Specify destinations for the LOG_ARCHIVE_DEST and LOG_ARCHIVE_DUPLEX_DEST parameter (you can also specify LOG_ARCHIVE_DUPLEX_DEST dynamically using the ALTER SYSTEM statement). Even when automatic archiving is enabled, you can use manual archiving for such actions as rearchiving an inactive group of filled redo log members to another location. An archived redo log file is a copy of one of the filled members of a redo log group. Destinations can be localwithin the local file system or an Oracle Automatic Storage Management (Oracle ASM) disk groupor remote (on a standby database). This process is only possible if the database is running in ARCHIVELOG mode. Oracle Data Guard Concepts and Administration for information about using the LOG_ARCHIVE_DEST_n initialization parameter for specifying a standby destination. This display tells you all the necessary information regarding the archived redo log settings for the current instance: The database is currently operating in ARCHIVELOG mode. specified by the LOG_ARCHIVE_DEST by Use capital letters (%T, %S, and %R) to pad the file name to the left with zeroes. To enter the same disk group more than once, subdirectories must be used. Sometimes archive destinations can fail, causing problems when you operate in automatic archiving mode. ENABLE indicates that the database can use the destination. You can change the archive A destination can be inactive, or valid, or disabled. These redundant copies help ensure that archived logs are always available in the event of a failure at one of the destinations. When you restart your > Enterprise Manager Console. Issue the ALTER not specified any LOG_ARCHIVE_DEST_n In this configuration archiving does not contend with other files required by the instance and can complete more quickly. Specifying %r causes the database to capture the resetlogs ID in the archived redo log file name. You can combine tracing levels by specifying a value equal to the sum of the individual levels that you would like to trace. You can choose automatic or manual archiving. You must have at least one local destination, which you can declare OPTIONAL or MANDATORY.
However, all LOG_ARCHIVE_DEST_n parameters must have a unique string. Several combinations of these characteristics are possible.
Oracle Database Backup and Recovery User's Guide for information about the Fast Recovery Area. All locations must be local. The database ignores the value and uses the number of MANDATORY destinations (in this example, 2). Describes the current instance, all archive destinations, and the current value, mode, and status of these destinations.
The LOG_ARCHIVE_DEST_n initialization parameter lets you specify whether a destination is OPTIONAL (the default) or MANDATORY.