---
title: Telegraf Documentation
description: Telegraf plugin for collecting metrics from Device Mapper Cache
url: https://docs.influxdata.com/telegraf/v1/input-plugins/dmcache/
estimated_tokens: 796
product: Telegraf
version: v1
---

-   Telegraf v1.3.0+

# Device Mapper Cache Input Plugin

This plugin provide a native collection for dmsetup based statistics for [dm-cache](https://docs.kernel.org/admin-guide/device-mapper/cache.html).

This plugin requires super-user permissions! Please make sure, Telegraf is able to run `sudo /sbin/dmsetup status --target cache` without requiring a password.

**Introduced in:** Telegraf v1.3.0 **Tags:** system **OS support:** linux

## Global configuration options

Plugins support additional global and plugin configuration settings for tasks such as modifying metrics, tags, and fields, creating aliases, and configuring plugin ordering. See [CONFIGURATION.md](/telegraf/v1/configuration/#plugins) for more details.

## Configuration

```toml
# Provide a native collection for dmsetup based statistics for dm-cache
# This plugin ONLY supports Linux
[[inputs.dmcache]]
  ## Whether to report per-device stats or not
  per_device = true
```

## Metrics

-   dmcache
    -   length
    -   target
    -   metadata\_blocksize
    -   metadata\_used
    -   metadata\_total
    -   cache\_blocksize
    -   cache\_used
    -   cache\_total
    -   read\_hits
    -   read\_misses
    -   write\_hits
    -   write\_misses
    -   demotions
    -   promotions
    -   dirty

## Tags

-   All measurements have the following tags:
    -   device

## Example Output

```text
dmcache,device=example cache_blocksize=0i,read_hits=995134034411520i,read_misses=916807089127424i,write_hits=195107267543040i,metadata_used=12861440i,write_misses=563725346013184i,promotions=3265223720960i,dirty=0i,metadata_blocksize=0i,cache_used=1099511627776ii,cache_total=0i,length=0i,metadata_total=1073741824i,demotions=3265223720960i 1491482035000000000
```

#### Related

-   [Configure plugins](/telegraf/v1/configure_plugins/)
-   [Device Mapper Cache Plugin Source](https://github.com/influxdata/telegraf/tree/v1.38.4/plugins/inputs/dmcache/README.md)