---
title: Telegraf Documentation
description: Telegraf plugin for collecting metrics from Bcache
url: https://docs.influxdata.com/telegraf/v1/input-plugins/bcache/
estimated_tokens: 1088
product: Telegraf
version: v1
---

-   Telegraf v0.2.0+

# Bcache Input Plugin

This plugin gathers statistics for the [block layer cache](https://docs.kernel.org/admin-guide/bcache.html) from the `stats_total` directory and `dirty_data` file.

**Introduced in:** Telegraf v0.2.0 **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
# Read metrics of bcache from stats_total and dirty_data
# This plugin ONLY supports Linux
[[inputs.bcache]]
  ## Bcache sets path
  ## If not specified, then default is:
  bcachePath = "/sys/fs/bcache"

  ## By default, Telegraf gather stats for all bcache devices
  ## Setting devices will restrict the stats to the specified
  ## bcache devices.
  bcacheDevs = ["bcache0"]
```

## Metrics

Tags:

-   `backing_dev` device backed by the cache
-   `bcache_dev` device used for caching

Fields:

-   `dirty_data`: Amount of dirty data for this backing device in the cache. Continuously updated unlike the cache set’s version, but may be slightly off
-   `bypassed`: Amount of IO (both reads and writes) that has bypassed the cache
-   `cache_bypass_hits`: Hits for IO that is intended to skip the cache
-   `cache_bypass_misses`: Misses for IO that is intended to skip the cache
-   `cache_hits`: Hits per individual IO as seen by bcache sees them; a partial hit is counted as a miss.
-   `cache_misses`: Misses per individual IO as seen by bcache sees them; a partial hit is counted as a miss.
-   `cache_hit_ratio`: Hit to miss ratio
-   `cache_miss_collisions`: Instances where data was going to be inserted into cache from a miss, but raced with a write and data was already present (usually zero since the synchronization for cache misses was rewritten)
-   `cache_readaheads`: Count of times readahead occurred.

## Example Output

```text
bcache,backing_dev="md10",bcache_dev="bcache0" dirty_data=11639194i,bypassed=5167704440832i,cache_bypass_hits=146270986i,cache_bypass_misses=0i,cache_hit_ratio=90i,cache_hits=511941651i,cache_miss_collisions=157678i,cache_misses=50647396i,cache_readaheads=0i
```

#### Related

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