---
title: InfluxDB internals
description: <h3 id="influxdb-storage-engine"><a href="/influxdb/v2/reference/internals/storage-engine/" target="">InfluxDB storage engine</a></h3> <p>An overview of the InfluxDB storage engine architecture.</p> <h3 id="influxdb-file-system-layout"><a href="/influxdb/v2/reference/internals/file-system-layout/" target="">InfluxDB file system layout</a></h3> <p>The InfluxDB file system layout depends on the operating system, package manager, or containerization platform used to install InfluxDB.</p> <h3 id="da
url: https://docs.influxdata.com/influxdb/v2/reference/internals/
estimated_tokens: 679
product: InfluxDB OSS v2
version: v2
---

# InfluxDB internals

This page documents an earlier version of InfluxDB OSS. [InfluxDB 3 Core](/influxdb3/core/) is the latest stable version.

#### API token hashing is enabled by default in InfluxDB OSS 2.9.0

Stronger token security: tokens are stored as hashes on disk, so a copy of the database file doesn’t expose usable tokens. Existing tokens are hashed on first startup and the original strings can’t be recovered afterward — **capture any plaintext tokens you still need before you upgrade**.

For more information, see [Token hashing](/influxdb/v2/admin/tokens/#token-hashing).

### [InfluxDB storage engine](/influxdb/v2/reference/internals/storage-engine/)

An overview of the InfluxDB storage engine architecture.

### [InfluxDB file system layout](/influxdb/v2/reference/internals/file-system-layout/)

The InfluxDB file system layout depends on the operating system, package manager, or containerization platform used to install InfluxDB.

### [Data retention in InfluxDB](/influxdb/v2/reference/internals/data-retention/)

The InfluxDB retention service checks for and removes data with timestamps beyond the defined retention period of the bucket the data is stored in.

### [InfluxDB runtime](/influxdb/v2/reference/internals/runtime/)

Learn how to collect Go runtime profiling and tracing information to help with InfluxDB performance analysis and debugging.

### [InfluxDB shards and shard groups](/influxdb/v2/reference/internals/shards/)

Learn the relationships between buckets, shards, and shard groups. InfluxDB organizes time series data into **shards** when storing data to disk. Shards are grouped into **shard groups**.

### [InfluxDB system buckets](/influxdb/v2/reference/internals/system-buckets/)

InfluxDB system buckets contain time series data used by and generated from the InfluxDB monitoring and alerting system and the task engine.

### [InfluxDB OSS metrics](/influxdb/v2/reference/internals/metrics/)

Get metrics about the workload performance of an InfluxDB OSS instance.