This documentation applies to the following versions of Splunk: 4.0 , 4.0.1 , 4.0.2 , 4.0.3 , 4.0.4 , 4.0.5 , 4.0.6 , 4.0.7 , 4.0.8 , 4.0.9 , 4.0.10
When you add data to Splunk, Splunk processes it and stores it in an index. By default, data you feed to Splunk is stored in the main index, but you can create and specify other indexes for Splunk to use for different data inputs.
Indexes are stored in databases, which are located in $SPLUNK_HOME/var/lib/splunk. A database is a directory named db_<starttime>_<endtime>_<seq_num>. An index is a collection of database directories.
In addition to the main index, Splunk comes preconfigured with a number of internal indexes. Internal indexes are named starting with an underscore (_). The internal indexes store audit, indexing volume, Splunk logging, and other data. You can see a full list of indexes in Splunk Web if you click on the Manager link in the upper right hand of Splunk Web and then click Indexes:
Read on in this section for information about ways to manage the indexing process, including:
Refer to: