Using ContinuousDataReplicator in a Fan-In Configuration
The following section provides the steps required to use CDR for data
replication and recovery in a Fan-In configuration based on multiple source
computers and a single destination.
Before You Begin
A full understanding of the following subjects will prove helpful:
Data Replication for a Fan-In Configuration
Required Capability:
Capabilities
and Permitted Actions
To use
CDR to replicate data from multiple source computers to a single destination
computer:
- Select all the computers on which to install CDR, those designated as the source
computers, and one designated as the destination computer. Verify that all selected computers meet the
System Requirements, and install the
ContinuousDataReplicator software on all selected computers.
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- Review
Destination
volume size in Best Practices
and Destination Computer Considerations.
- For CDR on Windows:
- The computer selected as the destination for a Fan-In configuration
must have Windows 2003 installed if you want to create Recovery Points.
- Review Log Space Requirements, accounting
for the number of source computers that will be sending Replication Logs to
the single destination computer.
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- For CDR on Windows:
- If you will be replicating application data, see the following:
- To configure replication and Recovery Point options, right-click the CDR Agent icon for the
destination computer, select
Properties, and click the
Fan-In tab. Configure your choices in the Pre/Post Process,
Recovery Points, and Storage Policy tabs. Settings in these tabs will be applied to all Replication Sets for all source computers
that use this computer as a destination.
-
For each source computer, do the following:
- Create a Replication Set.
Note the following:
- For CDR on UNIX, replication and Recovery Point options must be configured
on each source Replication Set.
- For CDR on Windows, the options specified in the previous step
should not also be specified when configuring the Replication Sets,
e.g., Recovery Point options should only be set on the Fan-In tab of the
destination Agent Properties, not on the Replication Set Properties on
the source computer.
-
Add a Replication Pair. For all source computers configured to Fan-In to the same destination computer,
every Replication Pair must use the same destination volume, but a different destination
path.
- Optionally, configure Throttling. Note the following for Fan-In
configurations:
- Throttling can be used to allow the destination computer sufficient
time to replay the logs it receives from all sources.
For CDR on Windows, this can also help prevent the destination from
running out of log space; for Fan-In configurations in particular, it is recommended
that you configure the destination computer to start throttling the source
computers when its log space runs low. For more information, see
Replication Activity Throttling.
- You might also configure the Throttling Amount on a source computer
to limit the maximum amount of data (in MB/second) it can transfer to the
destination, thus preventing a particular source from overwhelming the destination
during periods of high I/O. However, if the source computer is throttled
too much, it may not be able to transfer all its Replication Logs quickly
enough, and it could run out of space. For more information, see
Network Bandwidth Throttling.
-
Start Data Replication Activity.
-
Optionally, on the destination,
create Recovery Points; for more information, see
Recovery Points for a Fan-In Configuration.
Additional
Recommendations
Optionally, you can create Recovery Points.
- For CDR on Windows, Recovery Points are configured on the destination.
These settings will be applied to all Replication Sets for all source computers
that use this computer as a destination.
To create a Recovery Point for a Fan-In
configuration, see
Create a
Recovery Point Using CDR in a Fan-In Configuration. To delete a Recovery Point for a Fan-In
configuration, see
Delete a
Fan-In Recovery Point Using CDR.
To mount or unmount the snapshots of a Fan-In Recovery Point, see
Mount a
Fan-In Recovery Point Using CDR and
Unmount a
Fan-In Recovery Point Using CDR. Note that the snapshots of a Recovery Point created
for a Fan-In configuration can be mounted but not shared.
-
Recovery Points created for a Fan-In configuration use VSS or ONTAP as the
snap engine for creating snapshots. The use of snap engine is based on the
destination being used. When the destination is a fixed volume then VSS is used
and when the destination is a filer then ONTAP is used for the creating
snapshots.
Consider the following for ONTAP snapshots:
- Specify the user authentication details to be used for creating ONTAP
snapshots. The user information must be specified both in the
General tab of the replication set properties on the source and in the
Fan-In tab of the agent properties on the destination.
- Mounting of ONTAP snapshots is not supported in a Fan-In configuration.
- For CDR on UNIX, Recovery Points are configured on each Replication Set
on each source computer. Thus, any Replication Set sharing the same
destination can create Recovery Points. For instructions, see
Configure CDR Recovery Points and
Create a Recovery Point.
Additional
Recommendations
Recovery of Data for a Fan-In Configuration
For information about recovering replicated data, see
Recover Replicated Data.
For Copyback procedures, see
Copy Back File System
Data from a Fan-In Recovery Point.
Additional
Recommendations