This command is available only for Oracle and Microsoft
SQL Server.
Updates information about primary database log devices in the RASD.
ra_updatedevices
For Oracle, when ASM manages the redo log files and the disk group is changed by either adding or dropping disks, you must invoke the ra_updatedevices command to be sure the log device repository is updated with correct ASM storage information.
When ra_updatedevices is invoked, Replication Agent does the following:
Refreshes the archive log information
Deletes all of the data in its log device repository
If the device location is set, it is not overwritten.
Queries the primary database for information about all of its log devices
Re-populates the log device repository in the RASD with current information about primary database log devices returned by the primary database
If any log device associated with the primary database is added, dropped, extended, or moved at the primary data server, you must:
Stop replication (using quiesce or suspend) to put the Replication Agent instance in Admin state
Invoke ra_updatedevices to update the log device repository in the RASD
See the Replication Agent Administration Guide for more information.
The primary database need not be quiesced when you update
the log device repository.
If the primary data server writes to a new (or altered) log device before you update the log device repository, the Replication Agent instance will stop replication processing and go to Admin state.
Sybase recommends that you coordinate all log device changes at the primary database with updating the Replication Agent log device repository.
Because Replication Agent re-creates the entire log device repository when you invoke ra_updatedevices, any log device path that you modified previously (using ra_devicepath) is overwritten with the current log device information from the primary database.
For example:
ID=1 serverpath=/dev1 mirror=/dev1a
becomes the following when you change the server
path to “dev44”:
ID=1 serverpath=/dev44 mirror=/dev1a
If you need to alter the “default” path
for a log device (that is, the log device path returned by the primary
database), you must use the ra_devicepath command after you
invoke ra_updatedevices.
For each log device recorded in the RASD, you can set or change the disk device path with the ra_devicepath command.
If you do not specify a disk device path (using ra_devicepath), the value recorded for the disk device path is DEFAULT, and Replication Agent uses the value recorded for the server device path to find the log device.
The ra_updatedevices command is valid only when the Replication Agent instance is in Admin state.
(For Oracle) The Replication Agent uses the disk map file, to create mirror log devices, when log devices are created during xlog initialization and when devices are updated using the ra_updatedevices command. When Replication Agent is in the replicating state, it reads data from the mirrored disks specified in the map file.
The ra_updatedevices command updates the ASM disk map file. When executed the ASM disk map file is updated as follows:
ASM is queried to see if the disk groups required to read any redo logs have changed. If new disks have been added to any of the ASM disk groups, a default mirror entry is added in the ASM disk map file for the new disk.
The ASM disk group specified by the archive log path parameter is checked for new disks as well as the ASM disk group for each online redo log.
The ASM disk map file is updated before the log devices are updated to ensure any ASM disk path changes are included in updated log devices.
If new disk entries are added to the ASM disk map file, the log devices will not be updated in the repository. A message is returned to the user indicating that new entries are in the file that may need to be changed before devices are updated. The next time the ra_updatedevices command is executed, the log devices will be updated.
The Replication Agent command ra_helpdevice provides device information for the log device status where the device is physically located and if it is being mirrored to another device. The physical information is a simple path to a file or raw device. ASM uses disk groups with potentially many disks, the physical information for ASM devices is provided to show all disks required for the device. There will be one row output for each disk in the group where the device is stored.
