HP 3000 Manuals HP 3000 Manuals
Chapter 4 Hard Resynchronization
The hard resynchronization procedures are very similar to the standard
ALLBASE/SQL backup and recovery procedures. However, special precautions
and additional steps must be taken to accommodate the special needs of
ALLBASE/Replicate. In this chapter, each hard resynchronization method
is discussed along with ALLBASE/Replicate related issues. Then
recommendations are made for which method to use under specific
circumstances.
Several methods for performing a hard resynchronization include:
* ISQL UNLOAD/LOAD.
* SQLUtil static STORE and RESTORE.
* SQLUtil dynamic STOREONLINE and its associated restore commands.
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Use the ISQL UNLOAD command to unload master DBEnvironment tables, one at
a time, and store them in individual files or transfer to a slave
DBEnvironment. You can only use UNLOAD when no users are writing to the
DBEnvironment tables you want to unload.
If you want to do a static store, and you are doing non-archive mode
logging or you are doing archive mode logging on MPE/iX, but do not have
TURBO STORE installed, use the SQLUtil STORE command. This stores the
complete image of the master DBEnvironment along with the DBECon file
containing the SCR information.
If you are using archive mode logging and have TURBO STORE software on
MPE/iX, the SQLUtil STOREONLINE command is the preferred method.
STOREONLINE stores an image of a master DBEnvironment while that
DBEnvironment continues in use. It stores the image of the DBECon file
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The following methods cannot be used for hard resynchronization at this
time due to internal product limitations:
* SQLUtil static STORE PARTIAL and RESTORE PARTIAL.
* SQLUtil dynamic STOREONLINE PARTIAL and its associated restore
commands.
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When you perform Database Administration (DBA) tasks during hard
resynchronization, you often have two processes running at the same time
against that DBEnvironment. For example, you can connect to the master
through ISQL in one session. At the same time, you can connect to the
same master with SQLUtil in another session. You can hold locks in one
session while using SQLUtil in another session.
While this activity is taking place on the master, you can have two more
sessions for performing similar activities against the slave
DBEnvironment. The examples in this chapter all make use of two sessions
on the master and two sessions on the slave for DBA functions associated
with hard resynchronization. Each of the windows (A, B, X, Y) in the
following examples could instead be a separate terminal.
NOTE
* In window A on the master, or window X on the slave, you
will be in the group where you normally invoke ISQL. In our
examples, we invoke ISQL from a group that contains the
DBECon file. If you choose to invoke ISQL from a different
location, modify the example instructions accordingly. In
window A on the master, or window X on the slave, you will
be placing any required locks.
* In window B on the master, or window Y on the slave, you are
in the group where the DBECon file is located. Sometimes
the ALLBASE/Replicate applications are running in this
window. If the applications are not running, this window is
used for DBA operations that affect the DBECon file or the
DBEnvironment directly.
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