Standby_Root=standby-rootfile
Identifies the name of the standby database root file to which
the replication servers on the master database send replication
data.
Applicable to: Master database
Required or Required the first time you enter the
Optional: Replicate After_Journal Start command and
any time you specify other Replication Startup
qualifiers. Optional on all other invocations.
Default Value: None
You must include the Standby_Root qualifier the first time you
enter the Replicate After_Journal Start command (unless you have
preconfigured the Standby_Root qualifier using the Replication
After_Journal Configure command). This ensures that the master
database communicates with the standby database you specify
as the recipient of replication operations. If you omit the
Standby_Root qualifier on subsequent Replicate After_Journal
Start commands, the Hot Standby software retrieves the standby
database name from the header information in the database root
file.
Whenever you specify the Standby_Root qualifier, you must do the
following to ensure the command executes successfully:
o Specify the name of the standby database root file.
o Include a node name and directory path for remote network
communications. (You can define a logical name to identify the
master node.)
NOTE
When the standby database is configured in a VMScluster
system, the node name you specify with the Standby_Root
qualifier cannot be a cluster alias.
o Be able to access the standby database.
o Ensure that the standby database is opened for access prior to
starting replication operations on the master database.
You must open the standby database manually unless you
preconfigured the standby database. If you preconfigured the
database, you can start replication on both the master and
standby databases by entering a single Replicate After_Journal
Start command on the master database. The master database
automatically opens the standby database, if necessary.
The master and standby databases communicate using network
communications (for remote database access) or interprocess
communications (for local database access) according to how you
specify the database name. The following table describes how the
Hot Standby software chooses the method of communication:
If . . . Then . . .
You specify a node The Hot Standby software uses remote
name (for access to a network communications to ship the after-
standby database on a image journal log changes, unless the
remote node) specified node is the current node
You do not specify a The Hot Standby software uses the
node name following communications to ship the
after-image journal log changes:
o Local interprocess communications on
the local node
o Remote network communications on all
other nodes and across the cluster
The Hot Standby software compares and verifies the master
database (that you specify with the Master_Root qualifier)
against the standby database (that you specify with the Standby_
Root qualifier). The purpose of this verification is to ensure
that both databases are identical transactionally.
If replication operations are not started on the standby database
when you invoke the Replicate After_Journal Start command on
the master database, the Hot Standby software attempts to start
replication on the standby database using the default replication
attributes configured in the database root file before starting
replication on the master database.