You can create data marts, load data mart data, and accelerate
queries on one or more secondary servers in a high-availability cluster.
By using secondary servers for Informix® Warehouse Accelerator, you
have greater flexibility in a mixed-workload environment. For example,
you can dedicate the primary server for OLTP transactions and use
a secondary server for processing the warehouse analytic queries.
Configure the secondary servers by modifying the ONCONFIG file of
each secondary server, connecting one of the secondary servers to
an accelerator, and copying the sqlhosts entry in the sqlhosts file
to each server in the cluster.
Before you begin
The following prerequisites are required:
- Configure the high-availability cluster for the Informix database
server.
About this task
High-availability secondary servers include shared-disk
(SD) secondary servers, high-availability data replication (HDR) secondary
servers, and remote stand-alone (RS) secondary servers. To configure
the servers in a high-availability cluster to use Informix Warehouse Accelerator, follow
these steps. You can choose to configure Informix Warehouse Accelerator on a
subset of the secondary servers in the cluster.
Procedure
- Set the UPDATABLE_SECONDARY configuration parameter in
the ONCONFIG file on each secondary server that you plan to use for Informix Warehouse Accelerator.
This configuration parameter sets the number of connections
to establish to the primary server. For the Informix Warehouse Accelerator connection,
you can set this value to 1. (Depending on
the number and workload of your client applications, you might need
to set this configuration parameter to a higher value.)
- Add
a dwavp virtual processor to the VPCLASS configuration parameter in
the ONCONFIG file on each secondary server that you plan to use for Informix Warehouse Accelerator.
For example, VPCLASS dwavp,num=1.
- Make sure that each secondary server has access to the
required sbspace as described in Preparing the Informix database server.
- Restart each secondary server for which you modified the
ONCONFIG file for the changes to take effect.
-
Connect one of the servers in the cluster to an accelerator.
See Create an accelerator.
When the accelerator
is connected to the Informix database
server, the sqlhosts file on the Informix database
server is updated. You will use the new sqlhosts entry in the sqlhosts file
in the next step.
- Copy the sqlhosts entry that you created in the previous
step to the sqlhosts file in each server in the
cluster that you plan to use for Informix Warehouse Accelerator.
Important: Do not change any of the text in the
sqlhosts entry. The sqlhosts entry is stored in the server system
catalog and the sqlhosts entry must be identical on all the servers
so that they can communicate with Informix Warehouse Accelerator.
Results
After you configure the servers in a high-availability
cluster for Informix Warehouse Accelerator,
when you deploy a data mart from the primary server or any of the
secondary servers, the data mart definitions are replicated to all
the servers in the cluster. Any changes to the state of a data mart
that occur on one of the servers are replicated to all the servers
in the cluster.
Important: If the primary server fails
while you are performing a data mart operation (for example, creating
or loading a data mart), the data mart operation might fail. After
a secondary server successfully becomes a new primary server, try
any failed data mart operations again. If the primary failover caused
the deploying or the loading of the data mart to fail, you must drop
the data mart, create it, and load it again.