Redis®*: Prometheus

Prometheus metrics

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With Stackhero, you can easily retrieve metrics in Prometheus format for each of your services. This guide provides a detailed description of each Stackhero for Redis metric that is available. Keep in mind that all metric names are prefixed with redis_ when returned to Prometheus.

• shutdown_in_milliseconds: The maximum time remaining for replicas to catch up with replication before completing the shutdown sequence. This field is only present during shutdown.

• connected_clients: Number of client connections (excluding connections from replicas).

• cluster_connections: An approximation of the number of sockets used by the cluster's bus.

• maxclients: The value of the maxclients configuration directive. This is the upper limit for the sum of connected_clients, connected_slaves, and cluster_connections.

• client_recent_max_input_buffer: Largest input buffer among current client connections.

• client_recent_max_output_buffer: Largest output buffer among current client connections.

• blocked_clients: Number of clients pending on a blocking call (such as BLPOP, BRPOP, BRPOPLPUSH, BLMOVE, BZPOPMIN, BZPOPMAX).

• tracking_clients: Number of clients being tracked (CLIENT TRACKING).

• clients_in_timeout_table: Number of clients in the clients timeout table.

• used_memory: Total number of bytes allocated by Redis using its allocator (either standard libc, jemalloc, or an alternative allocator such as tcmalloc).

• used_memory_rss: Number of bytes that Redis allocated as seen by the operating system (a.k.a resident set size).

• used_memory_peak: Peak memory consumed by Redis.

• used_memory_peak_perc: The percentage of used_memory_peak out of used_memory.

• used_memory_overhead: The sum in bytes of all overheads that the server allocated for managing its internal data structures.

• used_memory_startup: Initial amount of memory consumed by Redis at startup in bytes.

• used_memory_dataset: Size in bytes of the dataset (used_memory_overhead subtracted from used_memory).

• used_memory_dataset_perc: The percentage of used_memory_dataset out of the net memory usage (used_memory minus used_memory_startup).

• total_system_memory: The total amount of memory that the Redis host has.

• used_memory_lua: Number of bytes used by the Lua engine.

• used_memory_scripts: Number of bytes used by cached Lua scripts.

• maxmemory: The value of the maxmemory configuration directive.

• maxmemory_policy: The value of the maxmemory-policy configuration directive.

• mem_fragmentation_ratio: Ratio between used_memory_rss and used_memory. Note that this doesn't only include fragmentation, but also other process overheads (see the allocator_* metrics), and also overheads like code, shared libraries, stack, etc.

• mem_fragmentation_bytes: Delta between used_memory_rss and used_memory. Note that when the total fragmentation bytes is low (few megabytes), a high ratio (e.g. 1.5 and above) is not an indication of an issue.

• allocator_frag_ratio: Ratio between allocator_active and allocator_allocated. This is the true (external) fragmentation metric (not mem_fragmentation_ratio).

• allocator_frag_bytes: Delta between allocator_active and allocator_allocated. See note about mem_fragmentation_bytes.

• allocator_rss_ratio: Ratio between allocator_resident and allocator_active. This usually indicates pages that the allocator can and probably will soon release back to the OS.

• allocator_rss_bytes: Delta between allocator_resident and allocator_active.

• rss_overhead_ratio: Ratio between used_memory_rss (the process RSS) and allocator_resident. This includes RSS overheads that are not allocator or heap related.

• rss_overhead_bytes: Delta between used_memory_rss (the process RSS) and allocator_resident.

• allocator_allocated: Total bytes allocated from the allocator, including internal-fragmentation. Normally the same as used_memory.

• allocator_active: Total bytes in the allocator active pages, this includes external-fragmentation.

• allocator_resident: Total bytes resident (RSS) in the allocator, this includes pages that can be released to the OS (by MEMORY PURGE, or just waiting).

• mem_not_counted_for_evict: Used memory that's not counted for key eviction. This is basically transient replica and AOF buffers.

• mem_clients_slaves: Memory used by replica clients. Replica buffers share memory with the replication backlog, so this field can show 0 when replicas don't trigger an increase in memory usage.

• mem_clients_normal: Memory used by normal clients.

• mem_cluster_links: Memory used by links to peers on the cluster bus when cluster mode is enabled.

• mem_aof_buffer: Transient memory used for AOF and AOF rewrite buffers.

• mem_replication_backlog: Memory used by replication backlog.

• mem_total_replication_buffers: Total memory consumed for replication buffer.

• mem_allocator: Memory allocator, chosen at compile time.

• active_defrag_running: When activedefrag is enabled, this indicates whether defragmentation is currently active, and the CPU percentage it intends to utilise.

• lazyfree_pending_objects: The number of objects waiting to be freed (as a result of calling UNLINK, or FLUSHDB and FLUSHALL with the ASYNC option).

• lazyfreed_objects: The number of objects that have been lazy freed.

• loading: Flag indicating if the load of a dump file is ongoing.

• async_loading: Currently loading replication dataset asynchronously while serving old data. This means repl-diskless-load is enabled and set to swapdb.

• current_cow_peak: The peak size in bytes of copy-on-write memory while a child fork is running.

• current_cow_size: The size in bytes of copy-on-write memory while a child fork is running.

• current_cow_size_age: The age, in seconds, of the current_cow_size value.

• current_fork_perc: The percentage of progress of the current fork process. For AOF and RDB forks it is the percentage of current_save_keys_processed out of current_save_keys_total.

• current_save_keys_processed: Number of keys processed by the current save operation.

• current_save_keys_total: Number of keys at the beginning of the current save operation.

• rdb_bgsave_in_progress: Flag indicating a RDB save is ongoing.

• rdb_last_save_time: Epoch-based timestamp of last successful RDB save.

• rdb_last_bgsave_status: Status of the last RDB save operation.

• rdb_last_bgsave_time_sec: Duration of the last RDB save operation in seconds.

• rdb_current_bgsave_time_sec: Duration of the ongoing RDB save operation if any.

• rdb_last_cow_size: The size in bytes of copy-on-write memory during the last RDB save operation.

• rdb_last_load_keys_expired: Number of volatile keys deleted during the last RDB loading.

• rdb_last_load_keys_loaded: Number of keys loaded during the last RDB loading.

• aof_enabled: Flag indicating AOF logging is activated.

• aof_rewrite_in_progress: Flag indicating a AOF rewrite operation is ongoing.

• aof_rewrite_scheduled: Flag indicating an AOF rewrite operation will be scheduled once the ongoing RDB save is complete.

• aof_last_rewrite_time_sec: Duration of the last AOF rewrite operation in seconds.

• aof_current_rewrite_time_sec: Duration of the ongoing AOF rewrite operation if any.

• aof_last_bgrewrite_status: Status of the last AOF rewrite operation.

• aof_last_write_status: Status of the last write operation to the AOF.

• aof_last_cow_size: The size in bytes of copy-on-write memory during the last AOF rewrite operation.

• module_fork_in_progress: Flag indicating a module fork is ongoing.

• module_fork_last_cow_size: The size in bytes of copy-on-write memory during the last module fork operation.

• aof_current_size: AOF current file size.

• aof_base_size: AOF file size on latest startup or rewrite.

• aof_pending_rewrite: Flag indicating an AOF rewrite operation will be scheduled once the ongoing RDB save is complete.

• aof_buffer_length: Size of the AOF buffer.

• aof_pending_bio_fsync: Number of fsync pending jobs in background I/O queue.

• aof_delayed_fsync: Delayed fsync counter.

• loading_start_time: Epoch-based timestamp of the start of the load operation.

• loading_total_bytes: Total file size.

• loading_rdb_used_mem: The memory usage of the server that had generated the RDB file at the time of the file's creation.

• loading_loaded_bytes: Number of bytes already loaded.

• loading_loaded_perc: Same value expressed as a percentage.

• loading_eta_seconds: ETA in seconds for the load to be complete.

• instantaneous_ops_per_sec: Number of commands processed per second.

• instantaneous_input_kbps: The network's read rate per second in KB/sec.

• instantaneous_output_kbps: The network's write rate per second in KB/sec.

• instantaneous_input_repl_kbps: The network's read rate per second in KB/sec for replication purposes.

• instantaneous_output_repl_kbps: The network's write rate per second in KB/sec for replication purposes.

• sync_full: The number of full resyncs with replicas.

• sync_partial_ok: The number of accepted partial resync requests.

• sync_partial_err: The number of denied partial resync requests.

• expired_stale_perc: The percentage of keys probably expired.

• expired_time_cap_reached_count: The count of times that active expiry cycles have stopped early.

• expire_cycle_cpu_milliseconds: The cumulative amount of time spent on active expiry cycles.

• evicted_clients: Number of evicted clients due to maxmemory-clients limit.

• pubsub_channels: Global number of pub/sub channels with client subscriptions.

• pubsub_patterns: Global number of pub/sub pattern with client subscriptions.

• pubsubshard_channels: Global number of pub/sub shard channels with client subscriptions.

• latest_fork_usec: Duration of the latest fork operation in microseconds.

• migrate_cached_sockets: The number of sockets open for MIGRATE purposes.

• slave_expires_tracked_keys: The number of keys tracked for expiry purposes (applicable only to writable replicas).

• active_defrag_hits: Number of value reallocations performed by the active defragmentation process.

• active_defrag_misses: Number of aborted value reallocations started by the active defragmentation process.

• active_defrag_key_hits: Number of keys that were actively defragmented.

• active_defrag_key_misses: Number of keys that were skipped by the active defragmentation process.

• tracking_total_keys: Number of keys being tracked by the server.

• tracking_total_items: Number of items, that is the sum of clients number for each key, that are being tracked.

• tracking_total_prefixes: Number of tracked prefixes in server's prefix table (only applicable for broadcast mode).

• role: Value is "master" if the instance is replica of no one, or "slave" if the instance is a replica of some master instance. Note that a replica can be master of another replica (chained replication).

• master_failover_state: The state of an ongoing failover, if any.

• master_replid: The replication ID of the Redis server.

• master_replid2: The secondary replication ID, used for PSYNC after a failover.

• master_repl_offset: The server's current replication offset.

• second_repl_offset: The offset up to which replication IDs are accepted.

• repl_backlog_active: Flag indicating replication backlog is active.

• repl_backlog_size: Total size in bytes of the replication backlog buffer.

• repl_backlog_first_byte_offset: The master offset of the replication backlog buffer.

• repl_backlog_histlen: Size in bytes of the data in the replication backlog buffer.

• master_host: Host or IP address of the master.

• master_port: Master listening TCP port.

• master_link_status: Status of the link (up/down).

• master_sync_in_progress: Indicate the master is syncing to the replica.

• slave_read_repl_offset: The read replication offset of the replica instance.

• slave_repl_offset: The replication offset of the replica instance.

• slave_priority: The priority of the instance as a candidate for failover.

• slave_read_only: Flag indicating if the replica is read-only.

• replica_announced: Flag indicating if the replica is announced by Sentinel.

• master_sync_total_bytes: Total number of bytes that need to be transferred. this may be 0 when the size is unknown (for example, when the repl-diskless-sync configuration directive is used).

• master_sync_read_bytes: Number of bytes already transferred.

• master_sync_left_bytes: Number of bytes left before syncing is complete (may be negative when master_sync_total_bytes is 0).

• master_sync_perc: The percentage master_sync_read_bytes from master_sync_total_bytes, or an approximation that uses loading_rdb_used_mem when master_sync_total_bytes is 0.

• connected_slaves: Number of connected replicas.

• min_slaves_good_slaves: Number of replicas currently considered good.

• current_eviction_exceeded_time: The time passed since used_memory last rose above maxmemory, in milliseconds.

• current_active_defrag_time: The time passed since memory fragmentation last was over the limit, in milliseconds.

• master_last_io_seconds_ago: Number of seconds since the last interaction with master.

• master_sync_last_io_seconds_ago: Number of seconds since last transfer I/O during a SYNC operation.

• master_link_down_since_seconds: Number of seconds since the link is down.

• total_eviction_exceeded_time: Total time used_memory was greater than maxmemory since server startup, in milliseconds.

• rdb_changes_since_last_save: Number of changes since the last dump.

• total_connections_received: Total number of connections accepted by the server.

• total_commands_processed: Total number of commands processed by the server.

• total_net_input_bytes: The total number of bytes read from the network.

• total_net_output_bytes: The total number of bytes written to the network.

• total_net_repl_input_bytes: The total number of bytes read from the network for replication purposes.

• total_net_repl_output_bytes: The total number of bytes written to the network for replication purposes.

• rejected_connections: Number of connections rejected because of maxclients limit.

• expired_keys: Total number of key expiration events.

• evicted_keys: Number of evicted keys due to maxmemory limit.

• keyspace_hits: Number of successful lookup of keys in the main dictionary.

• keyspace_misses: Number of failed lookup of keys in the main dictionary.

• used_cpu_sys: System CPU consumed by the Redis server, which is the sum of system CPU consumed by all threads of the server process (main thread and background threads).

• used_cpu_user: User CPU consumed by the Redis server, which is the sum of user CPU consumed by all threads of the server process (main thread and background threads).

• used_cpu_sys_children: System CPU consumed by the background processes.

• used_cpu_user_children: User CPU consumed by the background processes.

• used_cpu_sys_main_thread: System CPU consumed by the Redis server main thread.

• used_cpu_user_main_thread: User CPU consumed by the Redis server main thread.

• unexpected_error_replies: Number of unexpected error replies, that are types of errors from an AOF load or replication.

• total_error_replies: Total number of issued error replies, that is the sum of rejected commands (errors prior command execution) and failed commands (errors within the command execution).

• total_reads_processed: Total number of read events processed.

• total_writes_processed: Total number of write events processed.

• io_threaded_reads_processed: Number of read events processed by the main and I/O threads.

• io_threaded_writes_processed: Number of write events processed by the main and I/O threads.

• dump_payload_sanitizations: Total number of dump payload deep integrity validations (see sanitize-dump-payload config).

• total_forks: Total number of fork operations since the server start.

• total_active_defrag_time: Total time memory fragmentation was over the limit, in milliseconds.

• aof_rewrites: Number of AOF rewrites performed since startup.

• rdb_saves: Number of RDB snapshots performed since startup.