Databases Reference
In-Depth Information
We just configured Solr 1.4 as a separate application on the Tomcat server. We then
deployed the
solr-web
plugin on both the nodes. The
solr-web
plugin connects
to the Solr server. We configured the URL of our Solr server by changing the spring
configuration file. The Solr server uses a predefined schema for indexes. Liferay
Portal has its own schema for indexes. This schema file is supplied with the
solr-
web
plugin. We replaced the Solr server schema with the one provided with the
solr-web
plugin. After the preceding setup, when we create any data like a user or
blog, indexes of related data will be created in the Solr server.
Clustering best practices for the search engine
We learned about three options available to configure the search engine to work
properly in a clustered environment. Let's learn some of the best practices associated
with them.
• If the Portal application is expected to write a few indexes, it is recommended
to use the Cluster Link option. It is a lightweight option and can be
configured quickly.
• As indexes are accessed and changed frequently, a network filesystem-based
index storage can create issues related to concurrent file access. Hence, it is
advisable to avoid using that option even though it gives the best performance.
• If the Portal application is expected to have a large amount of data written
to search indexes, it is advisable to use the Solr search engine instead of
other options.
• The Solr server provides a master/slave server concept. If the Portal
application is expected to have a huge amount of read and write transactions
on search indexes, it is advisable to use that option to manage heavy loads.
• If the Cluster Link option is used to replicate search indexes and the Portal
application is expected to have frequent index changes, it is advisable to
configure multiple transport channels for the Cluster Link.
Quartz scheduler configuration
Liferay Portal includes a built-in scheduler engine. There are many features in
Liferay Portal that use a scheduler; for example, expiration of web content, LDAP
import functionality, and so on. Liferay also supports setting up a scheduler for
custom portlets. Internally, Liferay Portal uses the Quartz scheduler. Quartz is a
very popular open source scheduler engine. Quartz scheduler stores data related
to scheduled jobs in the Liferay database. Hence in a clustered environment, it is
possible that multiple nodes start the same job at the same time. This can create havoc.
To prevent this situation, we need to configure Quartz for the clustered environment.
