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Spotlight on Oracle 10.4 - Getting Started Guide

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Archive Destinations Page

Oracle records the changes made to data files in online redo logs, which can be used to recreate the database at any specified point in time. Oracle rotates the logging process through a set of two or more logs.

When an Oracle database has been set up for archiving, the redo logs that are not in use are copied to a set of mandatory or optional archive destinations. The database administrator (DBA) sets up several archive destinations for each instance in the database and can configure the number of destinations that must succeed when archiving. Up to 10 destinations can be defined per instance.

Archive destinations can be set up in different types of locations:

  • A location on the local server.
  • A location on a mapped network drive.
  • A Flashback recovery area, where Oracle can store the backup and recovery files that are used to recover data that has been lost or corrupted by logical errors. (For more information, see the Disk Storage | Recovery Area Page.)
  • An ASM disk group, where the Oracle kernel automatically manages the naming and placement of database files. (For more information, see the ASM | Diskgroups Page.)

Note: Spotlight reports equally on all archive destinations, with the exception of mapped network drives on Windows platforms, which do not support UNC naming of shares and prevent Spotlight from reporting on archive space or calculating time to failure.

To open the Archive Destinations page

  1. Select the Spotlight on Oracle connection in the Spotlight Browser.

  2. Click Disk Storage | Archive Destinations.

Charts on the Archive Destinations page

Chart

Description

Archive Log Rate

Archive Log Rate shows the aggregate rate (in megabytes per hour) at which data is being written from the Oracle database to ALL the defined archive destinations.

Note: There are no additional Spotlight metrics available for this chart.

Archive Free Space

Archive Free Space shows the amount of free space available in EACH archive destination defined for the Oracle database. There are usually at least two (and there can be as many as 10) archive destinations defined per Oracle instance.

If Spotlight has raised an Archive Destination Failure Alarm or Archive Critical Failure Alarm, you can use this chart to view:

  • How the archive space available has been filling over the specified period.
  • Which destinations are closest to failure.

A destination failure alarm indicates that at least one of the archive destinations is about to fail. A critical failure alarm indicates when the number of working destinations falls below the minimum number needed to archive successfully.

Note: To prevent archive destination failure, consider using an automated background process to purge archive destinations when they reach a specified threshold.

Archive Destination Grid

Archive Destination provides detailed information to complement the data shown for EVERY destination shown in the Archive Free Space chart above. Initially, the entries in this table are ranked in order of increasing time to failure. (Destinations whose time to failure is unknown are ranked first.)

Note: Information in the Archive Destination grid is updated every 5 minutes or at Spotlight's background refresh period (whichever is longer). Data Refresh Rates

Column

Description

Archive Destination

The name of the destination archive file.

Status

The current status of the destination in V$ARCHIVE_DEST — VALID, INACTIVE, DEFERRED, ERROR, DISABLED, BAD PARAM, ALTERNATE, or FULL.

Destination

The location where the archive is stored. This may be:

  • A location on the local server.
  • A location on a mapped network drive.
  • A Flashback recovery area.
  • An ASM disk group.

Destination total (MB)

The total size of the archive destination target.

Destination free (MB)

The total amount of free space available for the archive destination target.

Destination usable (MB)

The total amount of usable space for the archive destination target.

This is the same as the Destination free value if the archive destination is on a filesystem, or on an ASM diskgroup with EXTERNAL redundancy.

Notes:

  • The value for Destination usable may be negative if the archive destination is on an ASM diskgroup with NORMAL or HIGH redundancy and there is not enough available space for disk failover redundancy.
  • If the destination is in a Flash recovery area, the value includes reclaimable space.
  • If the destination is in a Flash recovery area, and if the space available on the destination (set by the DB_RECOVERY_FILE_DEST parameter) is less than the space reported through the V$RECOVERY_FILE_DEST view, the value shown is space available on the destination.

Time to failure

If the archive log area is not backed up and purged, this is the amount of time before the archive log destination will become full. The projected time to failure is determined by recent log generation rates for the usable space in that destination.

If the destination is an ASM diskgroup set up for redundancy, the time to failure is the point at which the value of V$ASM_DISKGROUP.USABLE_FILE_MB will be zero.

Notes:

  • Spotlight bases its calculation of time to failure on the last three days of archived logs.
  • For Oracle RAC databases, the time-to-failure estimate on the current instance is valid ONLY if the Oracle instance is a stand-alone database. If the instance is part of an Oracle RAC cluster, the time to failure value in Spotlight on Oracle is NOT a true estimate for the cluster as a whole. It is an accurate "time to failure" ONLY if the current instance alone is archiving data. Spotlight on Oracle RAC provides a more accurate estimate for time to failure because it collects cluster-wide statistics for data rates and archive destinations.
  • Insufficient data to calculate a time to failure: Spotlight calculates the time to failure via the V$ARCHIVED_LOG table, and returns no estimate until the table contains at least 7 logs.
Notes

A text area that contains further information about the specified archive destination.

  • If the destination status is ERROR, this column shows an error message on why the destination failed.
  • If the destination type is not supported, or if the total and free space on the destination cannot be retrieved, the column explains why the space metrics and time-to-failure cannot be displayed.

Binding

A value in V$ARCHIVE_DEST that specifies how failure affects the archiving operation:

  • MANDATORY — Successful archival is required.
  • OPTIONAL — Successful archival is not required.

Destination type

Is the archived log destination PUBLIC or PRIVATE?

By default, all archived log destinations are PUBLIC. Only PUBLIC destinations can be modified at runtime using the ALTER SYSTEM SET or ALTER SESSION SET statements.

Log sequence

The number of the last archived redo log on this destination.

Re-open (sec)

The retry time to open a destination after an error.

Transmit mode

The mode in which data is transmitted across the network — SYNCHRONOUS, ASYNCHRONOUS, or PARALLELSYNC.

Valid for

The optional VALID_FOR attribute allows you to use the same initialization parameter file for both primary and standby databases.

 

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