Apache Solr Reference Guide Covering Apache Solr 6.0

SolrCloud Instances
In SolrCloud mode, it's best to leave the data and update log directories as the defaults Solr comes with and
simply specify the solr.hdfs.home. All dynamically created collections will create the appropriate directories
automatically under the solr.hdfs.home root directory.
Set solr.hdfs.home in the form hdfs://host:port/path
You should specify a lock factory type of ' hdfs' or none.
bin/solr start -c -Dsolr.directoryFactory=HdfsDirectoryFactory
-Dsolr.lock.type=hdfs
-Dsolr.hdfs.home=hdfs://host:port/path
This command starts Solr in SolrCloud mode, using the defined JVM properties.
Modifying solr.in.sh (*nix) or solr.in.cmd (Windows)
The examples above assume you will pass JVM arguments as part of the start command every time you use bi
n/solr to start Solr. However, bin/solr looks for an include file named solr.in.sh ( solr.in.cmd on
Windows) to set environment variables. By default, this file is found in the bin directory, and you can modify it to
permanently add the HdfsDirectoryFactory settings and ensure they are used every time Solr is started.
For example, to set JVM arguments to always use HDFS when running in SolrCloud mode (as shown above),
you would add a section such as this:
# Set HDFS DirectoryFactory & Settings
-Dsolr.directoryFactory=HdfsDirectoryFactory \
-Dsolr.lock.type=hdfs \
-Dsolr.hdfs.home=hdfs://host:port/path \
The Block Cache
For performance, the HdfsDirectoryFactory uses a Directory that will cache HDFS blocks. This caching
mechanism is meant to replace the standard file system cache that Solr utilizes so much. By default, this cache
is allocated off heap. This cache will often need to be quite large and you may need to raise the off heap memory
limit for the specific JVM you are running Solr in. For the Oracle/OpenJDK JVMs, the follow is an example
command line parameter that you can use to raise the limit when starting Solr:
-XX:MaxDirectMemorySize=20g
HdfsDirectoryFactory Parameters
The HdfsDirectoryFactory has a number of settings that are defined as part of the directoryFactory co
nfiguration.
Solr HDFS Settings
Parameter Example Value Default Description
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