81 lines
2.9 KiB
Markdown
81 lines
2.9 KiB
Markdown
---
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description: "Telegraf plugin for collecting metrics from Bcache"
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menu:
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telegraf_v1_ref:
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parent: input_plugins_reference
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name: Bcache
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identifier: input-bcache
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tags: [Bcache, "input-plugins", "configuration", "system"]
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introduced: "v0.2.0"
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os_support: "linux"
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related:
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- /telegraf/v1/configure_plugins/
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- https://github.com/influxdata/telegraf/tree/v1.36.1/plugins/inputs/bcache/README.md, Bcache Plugin Source
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---
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# Bcache Input Plugin
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This plugin gathers statistics for the [block layer cache](https://docs.kernel.org/admin-guide/bcache.html)
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from the `stats_total` directory and `dirty_data` file.
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**Introduced in:** Telegraf v0.2.0
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**Tags:** system
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**OS support:** linux
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[bcache]: https://docs.kernel.org/admin-guide/bcache.html
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## Global configuration options <!-- @/docs/includes/plugin_config.md -->
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In addition to the plugin-specific configuration settings, plugins support
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additional global and plugin configuration settings. These settings are used to
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modify metrics, tags, and field or create aliases and configure ordering, etc.
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See the [CONFIGURATION.md](/telegraf/v1/configuration/#plugins) for more details.
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[CONFIGURATION.md]: ../../../docs/CONFIGURATION.md#plugins
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## Configuration
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```toml @sample.conf
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# Read metrics of bcache from stats_total and dirty_data
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# This plugin ONLY supports Linux
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[[inputs.bcache]]
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## Bcache sets path
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## If not specified, then default is:
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bcachePath = "/sys/fs/bcache"
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## By default, Telegraf gather stats for all bcache devices
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## Setting devices will restrict the stats to the specified
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## bcache devices.
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bcacheDevs = ["bcache0"]
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```
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## Metrics
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Tags:
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- `backing_dev` device backed by the cache
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- `bcache_dev` device used for caching
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Fields:
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- `dirty_data`: Amount of dirty data for this backing device in the cache.
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Continuously updated unlike the cache set's version, but may be slightly off
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- `bypassed`: Amount of IO (both reads and writes) that has bypassed the cache
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- `cache_bypass_hits`: Hits for IO that is intended to skip the cache
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- `cache_bypass_misses`: Misses for IO that is intended to skip the cache
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- `cache_hits`: Hits per individual IO as seen by bcache sees them; a
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partial hit is counted as a miss.
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- `cache_misses`: Misses per individual IO as seen by bcache sees them; a
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partial hit is counted as a miss.
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- `cache_hit_ratio`: Hit to miss ratio
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- `cache_miss_collisions`: Instances where data was going to be inserted into
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cache from a miss, but raced with a write and data was already present
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(usually zero since the synchronization for cache misses was rewritten)
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- `cache_readaheads`: Count of times readahead occurred.
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## Example Output
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```text
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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
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```
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