90 lines
2.3 KiB
Markdown
90 lines
2.3 KiB
Markdown
# Telegraf plugin: bcache
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Get bcache stat from stats_total directory and dirty_data file.
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# Measurements
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Meta:
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- tags: `backing_dev=dev bcache_dev=dev`
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Measurement names:
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- dirty_data
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- bypassed
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- cache_bypass_hits
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- cache_bypass_misses
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- cache_hit_ratio
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- cache_hits
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- cache_miss_collisions
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- cache_misses
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- cache_readaheads
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### Description
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```
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dirty_data
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Amount of dirty data for this backing device in the cache. Continuously
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updated unlike the cache set's version, but may be slightly off.
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bypassed
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Amount of IO (both reads and writes) that has bypassed the cache
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cache_bypass_hits
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cache_bypass_misses
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Hits and misses for IO that is intended to skip the cache are still counted,
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but broken out here.
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cache_hits
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cache_misses
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cache_hit_ratio
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Hits and misses are counted per individual IO as bcache sees them; a
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partial hit is counted as a miss.
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cache_miss_collisions
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Counts instances where data was going to be inserted into the cache from a
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cache miss, but raced with a write and data was already present (usually 0
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since the synchronization for cache misses was rewritten)
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cache_readaheads
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Count of times readahead occurred.
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```
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# Example output
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Using this configuration:
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```
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[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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#
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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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When run with:
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```
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./telegraf -config telegraf.conf -input-filter bcache -test
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```
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It produces:
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```
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* Plugin: bcache, Collection 1
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> [backing_dev="md10" bcache_dev="bcache0"] bcache_dirty_data value=11639194
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> [backing_dev="md10" bcache_dev="bcache0"] bcache_bypassed value=5167704440832
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> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_bypass_hits value=146270986
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> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_bypass_misses value=0
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> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_hit_ratio value=90
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> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_hits value=511941651
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> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_miss_collisions value=157678
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> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_misses value=50647396
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> [backing_dev="md10" bcache_dev="bcache0"] bcache_cache_readaheads value=0
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```
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