Metrics for MemoryDB
The Amazon/MemoryDB
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 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 
AuthenticationFailures 
The total number of failed attempts to authenticate to Redis using the AUTH command.
You can find more information about individual authentication failures
using the ACL LOG 
Count 
BytesUsedForMemoryDB 
The total number of bytes allocated by MemoryDB for all purposes, including the dataset, buffers, and so on.  Bytes 
Dimension: Tier=SSD for clusters using Data tiering: The total number of bytes used by SSD.

Bytes  
Dimension: Tier=Memory for clusters using Data tiering: The total number
of bytes used by memory. This is the value of used_memory statistic at Redis
INFO 
Bytes  
BytesReadFromDisk 
The total number of bytes read from disk per minute. Supported only for clusters using Data tiering.  Bytes 
BytesWrittenToDisk 
The total number of bytes written to disk per minute. Supported only for clusters using Data tiering.  Bytes 
CommandAuthorizationFailures 
The total number of failed attempts by users to run commands they don’t have permission
to call. You can find more information about individual authentication
failures using the ACL
LOG 
Count 
CurrConnections 
The number of client connections, excluding connections from read
replicas. MemoryDB uses two to four of the connections to monitor the
cluster in each case. This is derived from the connected_clients statistic at Redis INFO 
Count 
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 
Dimension: Tier=Memory for clusters using Data tiering. The number of items in memory. 
Count  
Dimension: Tier=SSD (solid state drives) for clusters using Data tiering. The number of items in SSD. 
Count  
DatabaseMemoryUsagePercentage 
Percentage of the memory available for the cluster that is in use. This is calculated using used_memory/maxmemory from Redis INFO 
Percent 
DB0AverageTTL 
Exposes avg_ttl of DBO from the keyspace statistic of Redis INFO 
Milliseconds 
EngineCPUUtilization 
Provides CPU utilization of the Redis engine thread. Because Redis is singlethreaded, you can
use this metric to analyze the load of the Redis process itself. The
Note On a MemoryDB host, background processes monitor the host to provide a managed database
experience. These background processes can take up a significant
portion of the CPU workload. This is not significant on larger
hosts with more than two vCPUs. But it can affect smaller hosts
with 2vCPUs or fewer. If you only monitor the

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 
IsPrimary 
Indicates whether the node is primary node of current shard. The metric can be either 0 (not primary) or 1 (primary).  Count 
KeyAuthorizationFailures 
The total number of failed attempts by users to access keys they don’t have permission
to access. You can find more information about individual authentication
failures using the ACL
LOG 
Count 
KeyspaceHits 
The number of successful readonly key lookups in the main dictionary. This is derived from keyspace_hits statistic at Redis INFO 
Count 
KeyspaceMisses 
The number of unsuccessful readonly key lookups in the main dictionary. This is derived from keyspace_misses statistic at Redis INFO 
Count 
KeysTracked 
The number of keys being tracked by Redis key tracking as a percentage of
trackingtablemaxkeys . Key tracking is used to aid
clientside caching and notifies clients when keys are modified.

Count 
MaxReplicationThroughput 
The maximum observed replication throughput during the last measurement cycle.  Bytes per second 
MemoryFragmentationRatio 
Indicates the efficiency in the allocation of memory of the Redis engine. Certain
thresholds signify different behaviors. The recommended value is to have
fragmentation above 1.0. This is calculated from the
mem_fragmentation_ratio statistic of Redis INFO 
Number 
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 
NumItemsReadFromDisk 
The total number of items retrieved from disk per minute. Supported only for clusters using Data tiering.  Count 
NumItemsWrittenToDisk 
The total number of items written to disk per minute. Supported only for clusters using Data tiering.  Count 
PrimaryLinkHealthStatus 
This status has two values: 0 or 1. The value 0 indicates that data in the MemoryDB primary node is not in sync with Redis on EC2. The value of 1 indicates that the data is in sync.  Boolean 
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 cluster.
This is derived from the master_repl_offset statistic at
Redis INFO 
Bytes 
ReplicationDelayedWriteCommands 
Number of commands that were delayed due to exceeding the maximum replication throughput.  Count 
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 
The following are aggregations of certain kinds of commands, derived from info commandstats. The commandstats section provides statistics based on the command type, including the number of calls.
For a full list of available commands, see redis commands
Metric  Description  Unit 

EvalBasedCmds 
The total number of commands for evalbased commands. This is derived from the Redis
commandstats statistic. This is derived from the Redis
commandstats statistic by summing eval,
evalsha. 
Count 
GeoSpatialBasedCmds 
The total number of commands for geospatialbased commands. This is derived from the
Redis commandstats statistic. It's derived by summing all
of the geo type of commands:
geoadd, geodist, geohash,
geopos, georadius, and
georadiusbymember. 
Count 
GetTypeCmds 
The total number of readonly type commands. This is derived from
the Redis commandstats statistic by summing all of the
readonly type commands (get,
hget, scard,
lrange, and so on.) 
Count 
HashBasedCmds 
The total number of commands that are hashbased. This is derived from the Redis
commandstats statistic by summing all of the commands
that act upon one or more hashes (hget,
hkeys, hvals,
hdel, and so on). 
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, and so
on.). 
Count 
JsonBasedCmds 
The total number of commands that are JSONbased. This is derived from the Redis commandstats statistics by summing all of the commands that act upon one or more JSON document objects.

Count 
KeyBasedCmds 
The total number of commands that are keybased. 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, and so on.). 
Count 
ListBasedCmds 
The total number of commands that are listbased. This is derived from the Redis
commandstats statistic by summing all of the commands
that act upon one or more lists (lindex,
lrange, lpush,
ltrim, and so on). 
Count 
PubSubBasedCmds 
The total number of commands for pub/sub functionality.
This is derived from the Redis commandstats statistics by summing all of the commands used for pub/sub functionality:
psubscribe, publish, pubsub, punsubscribe, subscribe, and unsubscribe. 
Count 
SetBasedCmds 
The total number of commands that are setbased. This is derived from the Redis
commandstats statistic by summing all of the commands
that act upon one or more sets (scard,
sdiff, sadd,
sunion, and so on). 
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, and so
on.) 
Count 
SortedSetBasedCmds 
The total number of commands that are sorted setbased. This is derived from the Redis
commandstats statistic by summing all of the commands
that act upon one or more sorted sets (zcount,
zrange, zrank,
zadd, and so on). 
Count 
StringBasedCmds 
The total number of commands that are stringbased. This is derived from the Redis
commandstats statistic by summing all of the commands
that act upon one or more strings (strlen,
setex, setrange, and so
on). 
Count 
StreamBasedCmds 
The total number of commands that are streambased. This is derived from the Redis
commandstats statistic by summing all of the commands
that act upon one or more streams data types (xrange,
xlen, xadd,
xdel, and so on). 
Count 