How data is stored physically in elastic search?

Question

If I navigate to Data directory of elastic search :

/nodes/0/indices/gb

Here what tree command shows :

├── 0
│   ├── index
│   │   ├── segments_         


        

Answer 1

All those files contain data and each contains a specific type of data (inverted index, field data, document values, etc). The files in the index sub-folder are files created by Lucene in order to store all the needed data:

• cfe and cfs files are compound files
• liv files are live document files
• si files are segment info files
• ...

There are many more file types available (term frequency, term proximity, etc) as can be seen in the first link I gave above. All those files are binary files that you cannot simply view with a text editor. You can use the Luke tool from the Lucene Toolbox in order to view the content of those files.