Memcache

Supported OS Linux Mac OS

통합 버전6.0.0
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Overview

The Agent’s Memcache check lets you track Memcache’s memory use, hits, misses, evictions, fill percent, and much more.

Setup

Installation

The Memcache check is included in the Datadog Agent package, so you don’t need to install anything else on your Memcache servers.

Configuration

Follow the instructions below to configure this check for an Agent running on a host. For containerized environments, see the Containerized section

When launching the Memcache server, set the binding protocol -B to binary or auto. Automatic (auto) is the default.

Metric collection

    Host

    To configure this check for an Agent running on a host:

    1. Edit the mcache.d/conf.yaml file, in the conf.d/ folder at the root of your Agent’s configuration directory. See the sample mcache.d/conf.yaml for all available configuration options:

      init_config:

instances:
  ## @param url - string - required
  ## url used to connect to the Memcached instance.
  #
  - url: localhost

    2. Restart the Agent to begin sending Memcache metrics to Datadog.

    Trace collection

    Datadog APM integrates with Memcache to see the traces across your distributed system. Trace collection is enabled by default in the Datadog Agent v6+. To start collecting traces:

    1. Enable trace collection in Datadog.
    2. Instrument your application that makes requests to Memcache.

    Containerized

    For containerized environments, see the Autodiscovery Integration Templates for guidance on applying the parameters below.

    ParameterValue
    <INTEGRATION_NAME>mcache
    <INIT_CONFIG>blank or {}
    <INSTANCE_CONFIG>{"url": "%%host%%","port": "11211"}
    Trace collection

    APM for containerized apps is supported on hosts running Agent v6+ but requires extra configuration to begin collecting traces.

    Required environment variables on the Agent container:

    ParameterValue
    <DD_API_KEY>api_key
    <DD_APM_ENABLED>true
    <DD_APM_NON_LOCAL_TRAFFIC>true

    See Tracing Kubernetes Applications and the Kubernetes Daemon Setup for a complete list of available environment variables and configuration.

    Then, instrument your application container and set DD_AGENT_HOST to the name of your Agent container.

    Log collection

    Available for Agent versions >6.0

    1. Add this configuration block to your mcache.d/conf.yaml file to start collecting your Memcached Logs:

      logs:
  - type: file
    path: /var/log/memcached.log
    source: memcached
    service: mcache

      Change the path and service parameter values and configure them for your environment.

    2. Restart the Agent to validate these changes.

    Validation

    Run the Agent’s status subcommand and look for mcache under the Checks section.

    Data Collected

    Metrics

    memcache.avg_item_size
    (gauge)    		The average size of an item.
    Shown as byte
    memcache.bytes
    (gauge)    		Current number of bytes used by this server to store items.
    Shown as byte
    memcache.bytes_read_rate
    (gauge)    		Rate of bytes read from the network by this server.
    Shown as byte
    memcache.bytes_written_rate
    (gauge)    		Rate of bytes written to the network by this server.
    Shown as byte
    memcache.cas_badval_rate
    (gauge)    		Rate at which keys are compared and swapped where the comparison (original) value did not match the supplied value.
    Shown as key
    memcache.cas_hits_rate
    (gauge)    		Rate at which keys are compared and swapped and found present.
    Shown as hit
    memcache.cas_misses_rate
    (gauge)    		Rate at which keys are compared and swapped and not found present.
    Shown as miss
    memcache.cmd_flush_rate
    (gauge)    		Rate of "flush_all" commands.
    Shown as command
    memcache.cmd_get_rate
    (gauge)    		Rate of "get" commands.
    Shown as command
    memcache.cmd_set_rate
    (gauge)    		Rate of "set" commands.
    Shown as command
    memcache.connection_structures
    (gauge)    		Number of connection structures allocated by the server.
    memcache.curr_connections
    (gauge)    		Number of open connections to this server.
    Shown as connection
    memcache.curr_items
    (gauge)    		Current number of items stored by the server.
    Shown as item
    memcache.delete_hits_rate
    (gauge)    		Rate at which delete commands result in items being removed.
    Shown as hit
    memcache.delete_misses_rate
    (gauge)    		Rate at which delete commands result in no items being removed.
    Shown as miss
    memcache.evictions_rate
    (gauge)    		Rate at which valid items are removed from cache to free memory for new items.
    Shown as eviction
    memcache.fill_percent
    (gauge)    		Amount of memory being used by the server for storing items as a percentage of the max allowed.
    Shown as percent
    memcache.get_hit_percent
    (gauge)    		Percentage of requested keys that are found present since the start of the memcache server.
    Shown as percent
    memcache.get_hits_rate
    (gauge)    		Rate at which keys are requested and found present.
    Shown as hit
    memcache.get_misses_rate
    (gauge)    		Rate at which keys are requested and not found.
    Shown as miss
    memcache.items.age
    (gauge)    		Age of the oldest item in the LRU
    Shown as second
    memcache.items.crawler_reclaimed_rate
    (gauge)    		Rate at which items freed by the LRU Crawler
    Shown as operation
    memcache.items.direct_reclaims_rate
    (gauge)    		Rate at which worker threads had to directly pull LRU tails to find memory for a new item
    Shown as operation
    memcache.items.evicted_nonzero_rate
    (gauge)    		Rate at which nonzero items which had an explicit expire time set had to be evicted from the LRU before expiring
    Shown as eviction
    memcache.items.evicted_rate
    (gauge)    		Rate at which items had to be evicted from the LRU before expiring
    Shown as eviction
    memcache.items.evicted_time
    (gauge)    		Seconds since the last access for the most recent item evicted from this class
    Shown as second
    memcache.items.evicted_unfetched_rate
    (gauge)    		Rate at which valid items evicted from the LRU which were never touched after being set
    Shown as eviction
    memcache.items.expired_unfetched_rate
    (gauge)    		Rate at which expired items reclaimed from the LRU which were never touched after being set
    Shown as eviction
    memcache.items.lrutail_reflocked_rate
    (gauge)    		Rate at which items found to be refcount locked in the LRU tail
    Shown as item
    memcache.items.moves_to_cold_rate
    (gauge)    		Rate at which items were moved from HOT or WARM into COLD
    Shown as item
    memcache.items.moves_to_warm_rate
    (gauge)    		Rate at which items were moved from COLD to WARM
    Shown as item
    memcache.items.moves_within_lru_rate
    (gauge)    		Rate at which active items were bumped within HOT or WARM
    Shown as item
    memcache.items.number
    (gauge)    		Number of items presently stored in this slab class
    Shown as item
    memcache.items.number_cold
    (gauge)    		Number of items presently stored in the COLD LRU
    Shown as item
    memcache.items.number_hot
    (gauge)    		Number of items presently stored in the HOT LRU
    Shown as item
    memcache.items.number_noexp
    (gauge)    		Number of items presently stored in the NOEXP class
    Shown as item
    memcache.items.number_warm
    (gauge)    		Number of items presently stored in the WARM LRU
    Shown as item
    memcache.items.outofmemory_rate
    (gauge)    		Rate at which the underlying slab class was unable to store a new item
    Shown as error
    memcache.items.reclaimed_rate
    (gauge)    		Rate at which entries were stored using memory from an expired entry
    Shown as operation
    memcache.items.tailrepairs_rate
    (gauge)    		Rate at which memcache self-healed a slab with a refcount leak
    Shown as operation
    memcache.limit_maxbytes
    (gauge)    		Number of bytes this server is allowed to use for storage.
    Shown as byte
    memcache.listen_disabled_num_rate
    (gauge)    		Rate at which the server has reached the max connection limit.
    Shown as event
    memcache.max_connections
    (gauge)    		Maximum number of connections to this server.
    Shown as connection
    memcache.pointer_size
    (gauge)    		Default size of pointers on the host OS (generally 32 or 64)
    Shown as bit
    memcache.rusage_system_rate
    (gauge)    		Fraction of time the CPU spent executing kernel code on behalf of this server process.
    Shown as fraction
    memcache.rusage_user_rate
    (gauge)    		Fraction of user time the CPU spent executing this server process.
    Shown as fraction
    memcache.slabs.active_slabs
    (gauge)    		Total number of slab classes allocated
    Shown as occurrence
    memcache.slabs.cas_badval_rate
    (gauge)    		Rate at which CAS commands failed to modify a value due to a bad CAS id
    Shown as key
    memcache.slabs.cas_hits_rate
    (gauge)    		Rate at which CAS commands modified this slab class
    Shown as operation
    memcache.slabs.chunk_size
    (gauge)    		The amount of space each chunk uses
    Shown as byte
    memcache.slabs.chunks_per_page
    (gauge)    		How many chunks exist within one page
    Shown as buffer
    memcache.slabs.cmd_set_rate
    (gauge)    		Rate at which set requests stored data in this slab class
    Shown as command
    memcache.slabs.decr_hits_rate
    (gauge)    		Rate at which decrs commands modified this slab class
    Shown as operation
    memcache.slabs.delete_hits_rate
    (gauge)    		Rate at which delete commands succeeded in this slab class
    Shown as operation
    memcache.slabs.free_chunks
    (gauge)    		Chunks not yet allocated to items or freed via delete
    Shown as buffer
    memcache.slabs.free_chunks_end
    (gauge)    		Number of free chunks at the end of the last allocated page
    Shown as buffer
    memcache.slabs.get_hits_rate
    (gauge)    		Rate at which get requests were serviced by this slab class
    Shown as hit
    memcache.slabs.incr_hits_rate
    (gauge)    		Rate at which incrs commands modified this slab class
    Shown as operation
    memcache.slabs.mem_requested
    (gauge)    		Number of bytes requested to be stored in this slab
    Shown as byte
    memcache.slabs.total_chunks
    (gauge)    		Total number of chunks allocated to the slab class
    Shown as buffer
    memcache.slabs.total_malloced
    (gauge)    		Total amount of memory allocated to slab pages
    Shown as byte
    memcache.slabs.total_pages
    (gauge)    		Total number of pages allocated to the slab class
    Shown as page
    memcache.slabs.touch_hits_rate
    (gauge)    		Rate of touches serviced by this slab class
    Shown as operation
    memcache.slabs.used_chunks
    (gauge)    		How many chunks have been allocated to items
    Shown as buffer
    memcache.slabs.used_chunks_rate
    (gauge)    		Rate at which chunks have been allocated to items
    Shown as buffer
    memcache.threads
    (gauge)    		Number of threads used by the current Memcached server process.
    Shown as thread
    memcache.total_connections_rate
    (gauge)    		Rate at which connections to this server are opened.
    Shown as connection
    memcache.total_items
    (gauge)    		Total number of items stored by this server since it started.
    Shown as item
    memcache.uptime
    (gauge)    		Number of seconds this server has been running.
    Shown as second

    The check only collects memcache.slabs.* metrics if you set options.slabs: true in mcache.d/conf.yaml. Likewise, it only collects memcache.items.* metrics if you set options.items: true.

    Events

    The Mcache check does not include any events.

    Service Checks

    memcache.can_connect
    Returns CRITICAL if the Agent is unable to connect to the monitored Memcached instance. Returns OK otherwise.
    Statuses: ok, critical

    Troubleshooting

    Need help? Contact Datadog support.

    Further Reading