Oracle enables the (ARCH) background archive process, or its foreground equivalent, to archive online redo log files to multiple destinations. Up to five destinations can be specified with the initialization parameter: LOG_ARCHIVE_DEST_n. This parameter defines a destination and attributes for the archive redo log file group.
The parameter number suffix is defined as the handle displayed by the fixed-table queries.
The destination can be a local disk-based file, or it can be a user-specified standby database that is either local or remote to the primary database. It has been observed that two archival destinations are not enough, though five or more is excessive and provides no additional benefit.
In the following code, you can see an example of usage of the parameter, where the first location of the archived redo log file is within the local hard disk.
A maximum of five destinations may be specified. The first destination specified is treated as the primary destination. The remaining destinations are secondary. At least one archive destination must be a local disk. One archive destination is MANDATORY, although none may actually be specified.
If no destinations are specified, the appropriate initialization parameters are used as defaults.
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This parameter introduced within Oracle8 is deprecated within Oracle8i.LOG_ARCHIVE_DEST_n must be used instead within Oracle8i and later.
This parameter specifies a second (duplex) archive destination. If LOG_ARCHIVE_DUPLEX_DEST is set to a NULL string ("") or (`'), it means that there is no duplex archive destination. The default of this parameter is a NULL string.
In the following simulation, we will set the parameter value of LOG_ARCHIVE_DUPLEX_DEST and LOG_ARCHIVE_DEST_n using the ALTER SYSTEM command within SQL*Plus.
Because these two parameters are dynamic, they can be changed using SQL*Plus.
LOG_ARCHIVE_DUPLEX_DEST is similar to the initialization parameter LOG_ARCHIVE_DEST.
This parameter specifies a second archive destination: the duplex archive destination. This duplex archive destination can be either a must-succeed or a best-effort archive destination, depending on how many archive destinations must succeed (as specified in the LOG_ARCHIVE_MIN_SUCCEED_DEST parameter). The default setting of a null string ("") or (' ') indicates that a duplex archive destination does not exist.
LOG_ARCHIVE_DUPLEX_DEST = filespec
There is no default value.
Range of values
Either a null string or any valid path or device name, except raw partitions
Note: If you are using Oracle Enterprise Edition, this parameter is deprecated in favor of the LOG_ARCHIVE_DEST_n parameters. If Oracle Enterprise Edition is not installed or it is installed but you have not specified any LOG_ARCHIVE_DEST_n parameters, this parameter is valid. The next lesson demonstrates how to detect and repair corrupted blocks.
Handle: A handle is a connection to the database server, which completes a transaction for the user.
Deprecated: When a certain feature or functionality is no longer advisable for use or will no longer be supported on the Oracle database server, that feature is called deprecated.