Amazon ElastiCache for Redis
ElastiCache for Redis User Guide (API Version 2015-02-02)

Metrics for Redis

The AWS/ElastiCache namespace includes the following Redis metrics.

With the exception of ReplicationLag and EngineCPUUtilization, these metrics are derived from the Redis info command. Each metric is calculated at the cache node level.

For complete documentation of the Redis info command, see http://redis.io/commands/info.

See Also

Metric Description Unit
ActiveDefragHits The number of value reallocations per minute performed by the active defragmentation process. This is derived from active_defrag_hits statistic at Redis INFO. Number
BytesUsedForCache The total number of bytes allocated by Redis for all purposes, including the dataset, buffers, etc. This is derived from used_memory statistic at Redis INFO. Bytes
CacheHits The number of successful read-only key lookups in the main dictionary. This is derived from keyspace_hits statistic at Redis INFO. Count
CacheMisses The number of unsuccessful read-only key lookups in the main dictionary. This is derived from keyspace_misses at Redis INFO. Count
CurrConnections The number of client connections, excluding connections from read replicas. ElastiCache uses two to three of the connections to monitor the cluster in each case. This is derived from the connected_clients statistic at Redis INFO. Count
EngineCPUUtilization

EngineCPUUtilization provides access to the Redis process CPU utilization to gain better insights into your Redis workloads. As Redis is single threaded and uses just one CPU core at any given point in time, EngineCPUUtilization provides more precise visibility into the load of the Redis process itself.

EngineCPUUtilization adds to the pre-existing CPUUtilization metric which exposes CPU utilization for the server instance as a whole including other operating system and management processes. We recommend that you use both EngineCPUUtilization and CPUUtilization metrics together to get a detailed understanding of CPU utilization for your Redis environment.

Percent
Evictions The number of keys that have been evicted due to the maxmemory limit. This is derived from the evicted_keys statistic at Redis INFO. Count
NewConnections The total number of connections that have been accepted by the server during this period. This is derived from the total_connections_received statistic at Redis INFO. Count
Reclaimed The total number of key expiration events. This is derived from the expired_keys statistic at Redis INFO. Count
ReplicationBytes For nodes in a replicated configuration, ReplicationBytes reports the number of bytes that the primary is sending to all of its replicas. This metric is representative of the write load on the replication group. This is derived from the master_repl_offset statistic at Redis INFO. Bytes
ReplicationLag This metric is only applicable for a node running as a read replica. It represents how far behind, in seconds, the replica is in applying changes from the primary node. Seconds
SaveInProgress This binary metric returns 1 whenever a background save (forked or forkless) is in progress, and 0 otherwise. A background save process is typically used during snapshots and syncs. These operations can cause degraded performance. Using the SaveInProgress metric, you can diagnose whether or not degraded performance was caused by a background save process. This is derived from the rdb_bgsave_in_progress statistic at Redis INFO. Count

EngineCPUUtilization availability

Nodes in a region created or replaced after the date and time specified in the following table will include the EngineCPUUtilization metric.

Region Region name EngineCPUUtilization availability
us-east-2 US East (Ohio) February 16, 2017 17:21 (UTC)
us-east-1 US East (N. Virginia) February 8, 2017 21:20 (UTC)
us-west-1 US West (N. California) February 14, 2017 22:23 (UTC)
us-west-2 US West (Oregon) Febrary 20, 2017 19:20 (UTC)
ap-northeast-1 Asia Pacific (Tokyo) February 14, 2017 19:58 (UTC)
ap-northeast-2 Asia Pacific (Seoul) Available on all nodes.
ap-northeast-3 Asia Pacific (Osaka-Local) Available on all nodes.
ap-south-1 Asia Pacific (Mumbai) February 7, 2017 02:51 (UTC)
ap-southeast-1 Asia Pacific (Singapore) February 13, 2017 23:40 (UTC)
ap-southeast-2 Asia Pacific (Sydney) February 14, 2017 03:33 (UTC)
ca-central-1 Canada (Central) Available on all nodes.
cn-north-1 China (Beijing) February 16, 2017 22:39 (UTC)
cn-northwest-2 China (Ningxia) Available on all nodes.
eu-central-1 EU (Frankfurt) February 15, 2017 00:46 (UTC)
eu-west-1 EU (Ireland) February 7, 2017 21:30 (UTC)
eu-west-2 EU (London) February 16, 2017 18:58 (UTC)
eu-west-3 EU (Paris) Available on all nodes.
sa-east-1 South America (São Paulo) February 7, 2017 04:35 (UTC)
us-gov-west-1 AWS GovCloud (US) February 16, 2017 20:11 (UTC)

These are aggregations of certain kinds of commands, derived from info commandstats:

Metric Description Unit
CurrItems The number of items in the cache. This is derived from the Redis keyspace statistic, summing all of the keys in the entire keyspace. Count
GetTypeCmds The total number of read-only type commands. This is derived from the Redis commandstats statistic by summing all of the read-only type commands (get, hget, scard, lrange, etc.) Count
HashBasedCmds The total number of commands that are hash-based. This is derived from the Redis commandstats statistic by summing all of the commands that act upon one or more hashes. Count
HyperLogLogBasedCmds The total number of HyperLogLog-based commands. This is derived from the Redis commandstats statistic by summing all of the pf type of commands (pfadd, pfcount, pfmerge, etc.). Count
KeyBasedCmds The total number of commands that are key-based. This is derived from the Redis commandstats statistic by summing all of the commands that act upon one or more keys across multiple data structures (del, expire, rename, etc.). Count
ListBasedCmds The total number of commands that are list-based. This is derived from the Redis commandstats statistic by summing all of the commands that act upon one or more lists. Count
SetBasedCmds The total number of commands that are set-based. This is derived from the Redis commandstats statistic by summing all of the commands that act upon one or more sets. Count
SetTypeCmds The total number of write types of commands. This is derived from the Redis commandstats statistic by summing all of the mutative types of commands that operate on data (set, hset, sadd, lpop, etc.) Count
SortedSetBasedCmds The total number of commands that are sorted set-based. This is derived from the Redis commandstats statistic by summing all of the commands that act upon one or more sorted sets. Count
StringBasedCmds The total number of commands that are string-based. This is derived from the Redis commandstats statistic by summing all of the commands that act upon one or more strings. Count
StreamBasedCmds The total number of commands that are stream-based. This is derived from the Redis commandstats statistic at Redis INFO by summing all of the commands that act upon one or more streams data type. Count