Bcache plugin

[cornerot]

Bcache statistics

[sparrc]

@cornerot thanks for the suggestion, any other details you could provide would be much appreciated!

[cornerot]

cache sets

/sys/fs/bcache/

• cset-uuid - UUIDs of cache sets

shell:  ls -d /sys/fs/bcache/*-*-*-*-*
output: /sys/fs/bcache/663955a3-765a-4737-a9fd-8250a7a78411

metrics

stats

path

• /sys/fs/bcache/663955a3-765a-4737-a9fd-8250a7a78411/stats_total

files

• bypassed
• cache_bypass_hits
• cache_bypass_misses
• cache_hit_ratio
• cache_hits
• cache_miss_collisions
• cache_misses
• cache_readaheads

description

• bypassed

  • Amount of IO (both reads and writes) that has bypassed the cache
    It contains pretty-printed values: 1036, 520.0k, 456.0M, 300.0G (k, M, G, T, P, E, Z, Y)

  shell:  cat bypassed
  output: 3.4T

• cache_bypass_misses

  • Hits and misses for IO that is intended to skip the cache are still counted,
    but broken out here.

  shell:  cat cache_bypass_hits
  output: 8450417

• cache_hit_ratio

  • Hits and misses are counted per individual IO as bcache sees them; a
    partial hit is counted as a miss (possible values 0 - 100)

  shell:  cat cache_hit_ratio
  output: 50

• cache_hits

  shell:  cat cache_hits
  output: 473978810

• cache_miss_collisions

  • Counts instances where data was going to be inserted into the cache from a
    cache miss, but raced with a write and data was already present (usually 0
    since the synchronization for cache misses was rewritten)

  shell:  cat cache_miss_collisions
  output: 154237

• cache_misses

  shell:  cat cache_misses
  output: 49838850

• cache_readaheads

  • Count of times readahead occurred.

  shell:  cat cache_readaheads
  output: 0

backing devices

/sys/fs/bcache//bdev<0..n>

• bdev<0..n> - Symlink to each of the attached backing devices.

shell:  ls -d /sys/fs/bcache/663955a3-765a-4737-a9fd-8250a7a78411/bdev+([[:digit:]])
output: /sys/fs/bcache/663955a3-765a-4737-a9fd-8250a7a78411/bdev0

shell:  readlink /sys/fs/bcache/663955a3-765a-4737-a9fd-8250a7a78411/bdev0
output: ../../../devices/virtual/block/md10/bcache

where md10 - system device name

metrics

dirty_data

path

• /sys/fs/bcache/663955a3-765a-4737-a9fd-8250a7a78411/bdev0

files

• dirty_data

description

• dirty_data

  • Amount of dirty data for this backing device in the cache.
    It contains pretty-printed values: 1036, 520.0k, 456.0M, 20.0G (k, M, G)

  shell:  cat dirty_data
  output: 11.0M

stats

path

• /sys/fs/bcache/663955a3-765a-4737-a9fd-8250a7a78411/bdev0/stats_total

files

• bypassed
• cache_bypass_hits
• cache_bypass_misses
• cache_hit_ratio
• cache_hits
• cache_miss_collisions
• cache_misses
• cache_readaheads

description

• same as for cache set

[cornerot]

plugin is almost ready

[cornerot]

#286