# What Does The Various Data Files Mean?

**URL:** <https://discuss.elastic.co/t/what-does-the-various-data-files-mean/301756>\
**Category:** Elasticsearch\
**Created:** [April 6, 2022, 12:37pm UTC](https://discuss.elastic.co/t/what-does-the-various-data-files-mean/301756 "2022-04-06T12:37:46Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![shaloms](https://avatars.discourse-cdn.com/v4/letter/s/b38774/32.png) [@shaloms](https://discuss.elastic.co/u/shaloms)\
**Post date:** [April 6, 2022, 12:37pm UTC](https://discuss.elastic.co/t/what-does-the-various-data-files-mean/301756/1 "2022-04-06T12:37:46Z")

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Hi All,

I'm new to Elasticsearch and this is my first time posting here, so apologies if I'm doing something incorrectly.  
Looking in the data directory, I see that there are lot of types of data files such as cfs, cfe, dvd etc.  
Can someone assist me in understanding what each file is used for or guide me to a documentation/blog on this subject?  
Also, if I see a lot of files of the same type, should this raise an alarm for me about the node's performance or is this normal? Is there a tool that I can use to explore these files from within the file system or should I only use the API?

Thanks!

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**Author:** ![spinscale](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/spinscale/32/25011_2.png) [@spinscale](https://discuss.elastic.co/u/spinscale)\
**Post date:** [April 7, 2022, 7:26am UTC](https://discuss.elastic.co/t/what-does-the-various-data-files-mean/301756/2 "2022-04-07T07:26:13Z")

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From a user perspective there is nothing to worry about, as Lucene will figure out things automatically. If you are interested what the fields are for, the Apache Lucene documentation is a great start:

> **[org.apache.lucene.codecs.lucene91 (Lucene 9.1.0 core API)](https://lucene.apache.org/core/9_1_0/core/org/apache/lucene/codecs/lucene91/package-summary.html#package.description)**
>
> declaration: package: org.apache.lucene.codecs.lucene91

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<div class="post-metadata">

**Author:** ![shaloms](https://avatars.discourse-cdn.com/v4/letter/s/b38774/32.png) [@shaloms](https://discuss.elastic.co/u/shaloms)\
**Post date:** [April 7, 2022, 12:55pm UTC](https://discuss.elastic.co/t/what-does-the-various-data-files-mean/301756/3 "2022-04-07T12:55:27Z")

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Got it!  
Thanks a lot @spinscale 🙂

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [May 5, 2022, 12:56pm UTC](https://discuss.elastic.co/t/what-does-the-various-data-files-mean/301756/4 "2022-05-05T12:56:23Z")

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