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Memcached

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Memcached collector can collect the running status metrics from Memcached instances, and collect the metrics to the Guance to help monitor and analyze various abnormal situations of Memcached.

Config

Preconditions

  • Memcached version >= 1.5.0. Already tested version:
    • 1.5.x
    • 1.6.x

Collector Configuration

Go to the conf.d/samples directory under the DataKit installation directory, copy memcached.conf.sample and name it memcached.conf. Examples are as follows:

[[inputs.memcached]]
  ## Servers' addresses.
  servers = ["localhost:11211"]
  # unix_sockets = ["/var/run/memcached.sock"]

  ## Set true to enable election
  election = true

  ## Collect extra stats
  # extra_stats = ["slabs", "items"]

  ## Collect interval.
  # units: "ns", "us", "ms", "s", "m", "h"
  interval = "10s"

[inputs.memcached.tags]
  # some_tag = "some_value"
  # more_tag = "some_other_value"
  # ...

Once configured, restart DataKit.

The collector can now be turned on by ConfigMap Injection Collector Configuration.

Metric

For all of the following data collections, the global election tags will added automatically, we can add extra tags in [inputs.memcached.tags] if needed:

 [inputs.memcached.tags]
  # some_tag = "some_value"
  # more_tag = "some_other_value"
  # ...

memcached

Tags & Fields Description
server
(tag)		 The memcached server address from which metrics are gathered.
accepting_conns Whether the server is currently accepting new connections. 1 means accepting, 0 means not accepting.
Type: int | (gauge)
Unit: N/A
auth_cmds Cumulative number of authentication commands handled, successful or failed.
Type: int | (count)
Unit: count
auth_errors Cumulative number of failed authentications.
Type: int | (count)
Unit: count
bytes Current number of bytes used to store items
Type: int | (gauge)
Unit: digital,B
bytes_read Cumulative bytes read by this server from the network.
Type: int | (count)
Unit: digital,B
bytes_written Cumulative bytes written by this server to the network.
Type: int | (count)
Unit: digital,B
cas_badval Cumulative CAS requests for which a key was found but the CAS value did not match.
Type: int | (count)
Unit: count
cas_hits Cumulative successful CAS requests.
Type: int | (count)
Unit: count
cas_misses Cumulative CAS requests against missing keys.
Type: int | (count)
Unit: count
cmd_flush Cumulative number of flush requests.
Type: int | (count)
Unit: count
cmd_get Cumulative number of retrieval requests.
Type: int | (count)
Unit: count
cmd_set Cumulative number of storage requests.
Type: int | (count)
Unit: count
cmd_touch Cumulative number of touch requests.
Type: int | (count)
Unit: count
conn_yields Cumulative number of times a connection yielded to another connection after hitting the -R limit.
Type: int | (count)
Unit: count
connection_structures Number of connection structures allocated by the server
Type: int | (gauge)
Unit: count
curr_connections Number of open connections
Type: int | (gauge)
Unit: count
curr_items Current number of items stored
Type: int | (gauge)
Unit: count
decr_hits Cumulative successful decr requests.
Type: int | (count)
Unit: count
decr_misses Cumulative decr requests against missing keys.
Type: int | (count)
Unit: count
delete_hits Cumulative delete requests that removed an item.
Type: int | (count)
Unit: count
delete_misses Cumulative delete requests for missing keys.
Type: int | (count)
Unit: count
evicted_unfetched Cumulative items evicted from the LRU that were never fetched after being set.
Type: int | (count)
Unit: count
evictions Cumulative valid items removed from cache to free memory for new items.
Type: int | (count)
Unit: count
expired_unfetched Cumulative expired items reclaimed from the LRU that were never fetched after being set.
Type: int | (count)
Unit: count
get_hits Cumulative keys requested and found present.
Type: int | (count)
Unit: count
get_misses Cumulative requested items that were not found.
Type: int | (count)
Unit: count
hash_bytes Bytes currently used by hash tables
Type: int | (gauge)
Unit: digital,B
hash_is_expanding Whether the hash table is currently being grown to a new size. 1 means expanding, 0 means not expanding.
Type: int | (gauge)
Unit: N/A
hash_power_level Current size multiplier for hash table
Type: int | (gauge)
Unit: count
incr_hits Cumulative successful incr requests.
Type: int | (count)
Unit: count
incr_misses Cumulative incr requests against missing keys.
Type: int | (count)
Unit: count
limit_maxbytes Number of bytes this server is allowed to use for storage
Type: int | (gauge)
Unit: digital,B
listen_disabled_num Cumulative number of times the server stopped accepting new connections after reaching maxconns.
Type: int | (count)
Unit: count
reclaimed Cumulative entries stored using memory reclaimed from an expired entry.
Type: int | (count)
Unit: count
threads Number of worker threads requested
Type: int | (gauge)
Unit: count
total_connections Cumulative connections opened since the server started.
Type: int | (count)
Unit: count
total_items Cumulative items stored since the server started.
Type: int | (count)
Unit: count
touch_hits Cumulative keys touched with a new expiration time.
Type: int | (count)
Unit: count
touch_misses Cumulative touch requests for items that were not found.
Type: int | (count)
Unit: count
uptime Seconds since the server started.
Type: int | (gauge)
Unit: time,s

memcached_items

Tags & Fields Description
server
(tag)		 The memcached server address from which metrics are gathered.
slab_id
(tag)		 Slab class ID from the stats items key.
age Age in seconds of the oldest item in the LRU for this slab class.
Type: int | (gauge)
Unit: time,s
crawler_reclaimed Cumulative items freed by the LRU crawler.
Type: int | (count)
Unit: count
direct_reclaims Cumulative worker threads that directly pulled LRU tails to find memory for a new item.
Type: int | (count)
Unit: count
evicted Cumulative items evicted from this slab class before expiring.
Type: int | (count)
Unit: count
evicted_nonzero Cumulative evicted items from this slab class that had an explicit non-zero expiration time.
Type: int | (count)
Unit: count
evicted_time Seconds since the last access for the most recent item evicted from this class
Type: int | (gauge)
Unit: time,s
evicted_unfetched Cumulative valid items evicted from this slab class that were never fetched after being set.
Type: int | (count)
Unit: count
expired_unfetched Cumulative expired items reclaimed from this slab class that were never fetched after being set.
Type: int | (count)
Unit: count
lrutail_reflocked Cumulative items found to be refcount locked in the LRU tail.
Type: int | (count)
Unit: count
moves_to_cold Cumulative items moved from HOT or WARM into COLD.
Type: int | (count)
Unit: count
moves_to_warm Cumulative items moved from COLD to WARM.
Type: int | (count)
Unit: count
moves_within_lru Cumulative active items bumped within HOT or WARM.
Type: int | (count)
Unit: count
number Number of items presently stored in this slab class
Type: int | (gauge)
Unit: count
number_cold Number of items presently stored in the COLD LRU
Type: int | (gauge)
Unit: count
number_hot Number of items presently stored in the HOT LRU
Type: int | (gauge)
Unit: count
number_noexp Number of items presently stored in the NOEXP class
Type: int | (gauge)
Unit: count
number_warm Number of items presently stored in the WARM LRU
Type: int | (gauge)
Unit: count
outofmemory Cumulative times this slab class could not store a new item due to memory pressure.
Type: int | (count)
Unit: count
reclaimed Cumulative entries stored using memory reclaimed from an expired entry.
Type: int | (count)
Unit: count
tailrepairs Cumulative self-healing repairs for slab items with leaked refcount references.
Type: int | (count)
Unit: count

memcached_slabs

Tags & Fields Description
server
(tag)		 The memcached server address from which metrics are gathered.
slab_id
(tag)		 Slab class ID from the stats slabs key.
active_slabs Total number of slab classes allocated
Type: int | (gauge)
Unit: count
cas_badval Cumulative CAS commands that failed to modify a value due to a bad CAS ID.
Type: int | (count)
Unit: count
cas_hits Cumulative CAS commands that modified this slab class.
Type: int | (count)
Unit: count
chunk_size The amount of space each chunk uses
Type: int | (gauge)
Unit: digital,B
chunks_per_page How many chunks exist within one page
Type: int | (gauge)
Unit: count
cmd_set Cumulative set requests that stored data in this slab class.
Type: int | (count)
Unit: count
decr_hits Cumulative decr commands that modified this slab class.
Type: int | (count)
Unit: count
delete_hits Cumulative successful delete commands in this slab class.
Type: int | (count)
Unit: count
free_chunks Chunks not yet allocated to items or freed via delete
Type: int | (gauge)
Unit: count
free_chunks_end Number of free chunks at the end of the last allocated page
Type: int | (gauge)
Unit: count
get_hits Cumulative get requests serviced by this slab class.
Type: int | (count)
Unit: count
incr_hits Cumulative incr commands that modified this slab class.
Type: int | (count)
Unit: count
total_chunks Total number of chunks allocated to the slab class
Type: int | (gauge)
Unit: count
total_malloced Total amount of memory allocated to slab pages
Type: int | (gauge)
Unit: digital,B
total_pages Total number of pages allocated to the slab class
Type: int | (gauge)
Unit: count
touch_hits Cumulative touch commands serviced by this slab class.
Type: int | (count)
Unit: count
used_chunks How many chunks have been allocated to items
Type: int | (gauge)
Unit: count

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