Use this task to restore a backup of a datastore and to recover
a messaging engine afterwards.
When a failure occurs which cannot be dealt with by the system,
you can restore the data store or data stores from a backup. You should also
restore the configuration files for the system, to ensure that it functions
as it did at the time the backup was taken, for more information about why
you should do this see Backing up the service integration environment.
Once you have restored the data store, you must restart the associated messaging engine.
When you restart
a messaging engine after restoring
a backup you must start it in Restart after restore mode,
to minimize the effects of the messaging engine not
being in synchronization with any other messaging engines it
was in communication with before the failure. If you restart the messaging engine in Normal mode, some of the new messages produced at this messaging engine might
be discarded by the receiving messaging engine,
for an indeterminate amount of time after restart. In Restart after
restore mode, previously transmitted messages might be resent,
potentially creating duplicates of messages that were produced before the
backup was taken. However new messages are not lost or duplicated (if this
is specified by the quality of service for the message).
You can only
restart a messaging engine in Restart
after restore mode by using the wsadmin client;
you cannot do it from the administrative console. You must only start a messaging engine in this mode when starting
the messaging engine for the first
time after restoring the backup. After the initial restart you can perform
further restarts as normal.
Restart
after restore mode is ignored if you start the server in Recovery mode.
If you require both a Recovery mode start and a Restart
after restore mode start:
- Start the server in recovery mode
- Wait for the startup to complete and for the server to stop
- Start the messaging engine in Restart
after restore mode
If you see the following message in the JVM System output file
SystemOut.log, this may indicate that you have
restored from a backup and restarted the
messaging engine without
using the
Restart after restore mode.
CWSIP0784E: Messaging engine: receivingME received a message from messaging engine: producingME that was
not expected.
To resolve this issue, stop the
messaging engine and
restart it in
Restart after restore mode.
Note: This message
may also appear in other situations, so you should only restart the messaging engine in Restart
after restore mode if you know you have restored a backup.
For
information on the JVM System output fileSystemOut.log and
how to view it, see Viewing the JVM logs.
You
can recover any number of messaging engines at
the same time, by following the actions below for each messaging engine in
turn.
- Change the initial state of the messaging engine to Stop,
so that the messaging engine will
not be automatically restarted by a server process:
- Use the administrative console to select the messaging engine by
clicking bus_name engine_name.
- In the Initial state list, click Stopped.
- Click OK.
- Save your changes to the master configuration, ensuring that you
select the Synchronize changes with Nodes check box.
- Stop the messaging engine if
it is running (see Stopping a messaging engine for
instructions on how to do this). If the messaging engine does
not respond, stop the server process which is hosting the messaging engine.
- Restore the backup of the data store which is accessed by the messaging engine, by referring to Restoring a data store.
- Restore the backup of the configuration files using the backupConfig command
(see Backing up and restoring administrative configurations).
This backup should have been taken at the same time as the data store backup.
- Restart any servers that were stopped by the failure.
- Restart the messaging engine in Restart
after restore mode by performing the following steps:
- Start the wsadmin client.
For
more information about the wsadmin client, see Wsadmin tool.
- Invoke the start command using the FLUSH parameter,
on the MBean for the messaging engine,
for example:
wsadmin>set myME [$AdminControl queryNames type=SIBMessagingEngine,*]WebSphere:platform=common,
cell=myCell,version=6.0.0.0,name=myNode.server1-myBus,
mbeanIdentifier=cells/myCell/nodes/myNode/servers/server1/sib-engines.xml#SIBMessagingEngine_1089294328702,
type=SIBMessagingEngine,node=myNode,process=server1
wsadmin>$AdminControl invoke $myME state
Stopped
wsadmin>$AdminControl invoke $myME start{"FLUSH"}
wsadmin>$AdminControl invoke $myME state
Started
A number of messages may be output to the JVM SystemOut.log file
to indicate the progress of the restart process.
- Check the JVM SystemOut.log file for the following
message that indicates that the restart was successful, in other words, no
failures occurred while attempting to restart the messaging engine.
CWSIP0783E: Messaging engine: messagingEngine started, flush of all delivery streams completed.
If
this message does not appear, a failure has occurred which has prevented the messaging engine from restarting. Resolve
the cause of the failure and repeat the Restart after restore procedure
until the restart is successful.