Adding upstream version 1.34.4.

Signed-off-by: Daniel Baumann <daniel@debian.org>

plugins/inputs/bcache/README.md

@@ -0,0 +1,65 @@
+# Bcache Input Plugin
+
+This plugin gathers statistics for the [block layer cache][bcache]
+from the `stats_total` directory and `dirty_data` file.
+
+⭐ Telegraf v0.2.0
+🏷️ system
+💻 linux
+
+[bcache]: https://docs.kernel.org/admin-guide/bcache.html
+
+## Global configuration options <!-- @/docs/includes/plugin_config.md -->
+
+In addition to the plugin-specific configuration settings, plugins support
+additional global and plugin configuration settings. These settings are used to
+modify metrics, tags, and field or create aliases and configure ordering, etc.
+See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
+
+[CONFIGURATION.md]: ../../../docs/CONFIGURATION.md#plugins
+
+## Configuration
+
+```toml @sample.conf
+# 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
+```