add bcache/README.md

plugins/bcache/README.md

@@ -0,0 +1,58 @@
+# Telegraf plugin: bcache
+
+Get bcache stat from stats_total directory and dirty_data file.
+
+# Measurements
+
+Meta:
+
+- tags: `backing_dev=dev bcache_dev=dev`
+
+Measurement names:
+
+- dirty_data
+- bypassed
+- cache_bypass_hits
+- cache_bypass_misses
+- cache_hit_ratio
+- cache_hits
+- cache_miss_collisions
+- cache_misses
+- cache_readaheads
+
+# Example output
+
+Using this configuration:
+
+```
+[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", ...]
+```
+
+When run with:
+
+```
+./telegraf -config telegraf.conf -filter bcache -test
+```
+
+It produces:
+
+```
+* Plugin: bcache, Collection 1
+> [backing_dev="md10" bcache_dev="bcache0"] bcache_dirty_data value=11639194
+> [backing_dev="md10" bcache_dev="bcache0"] bcache_bypassed value=5167704440832
+> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_bypass_hits value=146270986
+> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_bypass_misses value=0
+> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_hit_ratio value=90
+> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_hits value=511941651
+> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_miss_collisions value=157678
+> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_misses value=50647396
+> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_readaheads value=0
+```