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Table Of Contents
SQLFire preserves the order of DML statements applied to the distributed system (and queued to remote WAN
sites) only for a single thread of execution. See No Ordering Guarantee for DML in Separate Threads on page
136.
See also the vFabric SQLFire Release Notes for information about known issues associated with multi-site
deployments.
Prerequisites for WAN Replication
Note the prerequisites for conguring and using replication between two SQLFire clusters.
To use WAN replication between multiple SQLFire clusters:
Each SQLFire distributed system that participates in WAN replication must use one or more locators for member
discovery. WAN replication is not supported with multicast discovery.
WAN deployments increase the messaging demands on a SQLFire system. To avoid hangs related to WAN
messaging, always set conserve-sockets=false for SQLFire members that participate in a WAN deployment.
Tables that are WAN-enabled must be present in each distributed system that you want to connect.
You can congure both partitioned tables and replicated tables to use a gateway sender. However, you must
create replicated tables in the same server groups as the gateway sender(s) that you specify in the CREATE
TABLE statement.
You must start the entire WAN system before you populate tables with data. This is required so that the WAN
sites can remain in sync from the very beginning. Failing to do this causes exceptions during data update
operations.
See also Limitations of Multi-Site Replication on page 222.
Steps to Configure a Multi-site Deployment
To replicate a table's DML operations to one or more SQLFire clusters over a WAN, you congure the required
WAN features in each SQLFire cluster.
SQLFire provides SQL commands and extensions for creating and managing the gateway senders, gateways
receivers, and tables that are used for WAN replication.
Follow these steps to congure a multi-site deployment.
TopicDescriptionStep
Multi-site Deployment on page 205
Conguring Multi-site (WAN) Deployments
on page 219
Plan the topology of the connections among
the multiple clusters.
1
Congure Locators for WAN Member
Discovery on page 224
Start the locators for each cluster, specifying
the local cluster's distributed system ID and
the locator addresses associated with remote
clusters.
2
Starting and Conguring SQLFire Servers
on page 215
Start data stores in each cluster, specifying
the required server group memberships.
3
Create and Start Gateway Sender on page 225Optionally congure any disk stores that you
will use to persist DML operations that are
queued before sending to a remote cluster.
4
Create and Start Gateway Sender on page 225Congure a gateway sender in each SQLFire
cluster that will send its data to another
remote cluster for replication.
5
223
Configuring Multi-site (WAN) Deployments