Supported monitoring metrics

Preview

This feature is subject to the "Pre-GA Offerings Terms" in the General Service Terms section of the Service Specific Terms. Pre-GA features are available "as is" and might have limited support. For more information, see the launch stage descriptions.

This page lists Cloud Monitoring metrics available for Memorystore for Valkey, and describes what each metric measures.

Cloud Monitoring metrics

Metric name	Description
memorystore.googleapis.com/instance/clients/average_connected_clients	Mean current number of client connections across all nodes in the instance.
memorystore.googleapis.com/instance/clients/maximum_connected_clients	Maximum current number of client connections for a single node in the instance.
memorystore.googleapis.com/instance/clients/maximum_connection_duration	Maximum duration of a client connection for a single node in the instance.
memorystore.googleapis.com/instance/clients/total_connected_clients	Current number of client connectionsto the instance.
memorystore.googleapis.com/instance/stats/total_connections_received_count	Count of instance-level total client connections created in the last one minute.
memorystore.googleapis.com/instance/stats/total_rejected_connections_count	Number of connections rejected because of maxclients limit.
memorystore.googleapis.com/instance/commandstats/total_usec_count	The total time consumed per command.
memorystore.googleapis.com/instance/commandstats/total_calls_count	Total number of calls for this command in one minute.
memorystore.googleapis.com/instance/cpu/average_utilization	Mean CPU utilization across all nodes in the instance from 0.0 to 1.0.
memorystore.googleapis.com/instance/cpu/maximum_utilization	Maximum CPU utilization for a single node in the instance from 0.0 to 1.0.
memorystore.googleapis.com/instance/stats/average_expired_keys	Mean number of key expiration events for the primaries of all nodes in the instance.
memorystore.googleapis.com/instance/stats/maximum_expired_keys	Maximum number of key expiration events for a single node in the instance for the primary.
memorystore.googleapis.com/instance/stats/total_expired_keys_count	Total number of key expiration events across primaries of all nodes in the instance.
memorystore.googleapis.com/instance/stats/average_evicted_keys	Mean number of evicted keys due to memory capacity across primaries of all nodes in the instance.
memorystore.googleapis.com/instance/stats/maximum_evicted_keys	Maximum number of evicted keys for a single node in the instance due to memory capacity for the primary.
memorystore.googleapis.com/instance/stats/total_evicted_keys_count	Number of evicted keys due to memory capacity across primaries of all nodes in the instance.
memorystore.googleapis.com/instance/keyspace/total_keys	Number of keys stored in the instance.
memorystore.googleapis.com/instance/stats/average_keyspace_hits	Mean number of successful lookup of keys across all nodes in the instance.
memorystore.googleapis.com/instance/stats/maximum_keyspace_hits	Maximum number of successful lookup of keys for a single node in the instance.
memorystore.googleapis.com/instance/stats/total_keyspace_hits_count	Number of successful lookup of keys for the instance.
memorystore.googleapis.com/instance/stats/average_keyspace_misses	Mean number of failed lookup of keys across all nodes in the instance.
memorystore.googleapis.com/instance/stats/maximum_keyspace_misses	Maximum number of failed lookup of keys for a single node in the instance.
memorystore.googleapis.com/instance/stats/total_keyspace_misses_count	Total number of failed lookup of keys for the instance.
memorystore.googleapis.com/instance/memory/average_utilization	Mean memory utilization across all nodes in the instance. Value is from 0.0 to 1.0.
memorystore.googleapis.com/instance/memory/maximum_utilization	Maximum memory utilization for a single node in the instance from 0.0 to 1.0.
memorystore.googleapis.com/instance/memory/total_used_memory	Total memory usage of the instance.
memorystore.googleapis.com/instance/memory/size	Memory size of the instance.
memorystore.googleapis.com/instance/replication/average_ack_lag	Mean replication lag (in seconds) of replicas across all nodes in the instance. Replication lag (in seconds) indicates how far replicas are lagging behind primaries.
memorystore.googleapis.com/instance/replication/maximum_ack_lag	Maximum replication acknowledge lag (in seconds) for a single replica in the instance. Replication acknowledge lag (in seconds) indicates how far replication acknowledgements are lagging behind primaries.
memorystore.googleapis.com/instance/replication/average_offset_diff	Mean replication acknowledge offset diff (in bytes) across all nodes in the instance. Replication acknowledge offset diff means the number of bytes that have not been replicated between replicas and their primaries.
memorystore.googleapis.com/instance/replication/maximum_offset_diff	Maximum replication offset diff (in bytes) for a single node in the instance. Replication offset diff means the number of bytes that have not been replicated between a replicas and their primaries.
memorystore.googleapis.com/instance/stats/total_net_input_bytes_count	Count of incoming network bytes received by the instance endpoints.
memorystore.googleapis.com/instance/stats/total_net_output_bytes_count	Count of outgoing network bytes sent from the instance endpoints.

Persistence metrics

This sections lists persistence metrics and provides sample use cases for persistence metrics.

RDB persistence metrics

Metric name	Description
memorystore.googleapis.com/instance/persistence/load_count	Cumulative count of loads from dumpfile across the instance (AOF or RDB).
memorystore.googleapis.com/instance/persistence/rdb_saves_count	This metric shows the cumulative number of times your instance has taken an RDB snapshot (also known as save). This metric has a status_code field. To check if a snapshot has failed, you can filter the status_code field for the following error: 3 - INTERNAL_ERROR
memorystore.googleapis.com/instance/persistence/rdb_last_success_ages	This metric shows a distribution snapshot age for all nodes across the instance. Ideally you want to see the distribution have values that have less lag time (or the same time) than your snapshot frequency.
memorystore.googleapis.com/instance/persistence/rejected_writes_count	Cumulative count of denied write commands across the instance due to failure to persist.

AOF persistence metrics

Metric name	Description
memorystore.googleapis.com/instance/persistence/aof_fsync_lags	This metrics shows a distribution of the lag (from data write to durable storage sync) for all nodes in the instance. It is only emitted for instances with appendfsync=everysec. Ideally you want to see the distribution have values that have less lag time (or the same time) than your AOF sync frequency.
memorystore.googleapis.com/instance/persistence/aof_rewrite_count	This metric shows the cumulative number of times for your instance that a node has triggered an AOF rewrite. This metric has a status_code field. To check if AOF rewrites are failing, you can filter the status_code field for the following error: 3 - INTERNAL_ERROR

Sample use cases for persistence metrics

Checking if AOF write operations cause latency and memory pressure

Suppose that you detect increased latency or memory usage on your instance. In this case you may want to check if the extra usage is related to AOF persistence.

Since you know AOF rewrite operations can trigger transient load spikes, you can inspect the aof_rewrites_count metric which gives you the cumulative count of AOF rewrites over the lifetime of the instance. Suppose this metric shows you that increments in the rewrites count correspond to latency increases. In this circumstance you could address the issue by reducing the write rate or increasing the shard count to reduce the frequency of rewrites.

Checking if RDB save operations cause latency and memory pressure

Suppose that you detect increased latency or memory usage on your instance. In this case you may want to check if the extra usage is related to RDB persistence.

Since you know RDB save operations can trigger transient load spikes, you can inspect the rdb_saves_count metric which gives the cumulative count of RDB saves over the lifetime of the instance. Suppose this metric shows you that increments in the RDB saves count correspond to latency increases. In this circumstance you could reduce the RDB snapshot interval to lower the frequency of rewrites. You could also scale out the instance to reduce the baseline load levels.

Interpreting metrics for Memorystore for Valkey

As seen in the list above, many of the metrics share three categories: average, maximum, and total.

For Memorystore for Valkey, we provide average and maximum variations of the same metric so you can use them both to identify hotspotting for that metric family.

The total value for the metric is independent, and provides separate insight unrelated to the hotspotting purpose of average and maximum.

Understanding average and maximum metrics

Suppose you compare the average_keyspace_hits and maximum_keyspace_hits values for your instance. As the difference between the two metrics grows, a greater difference indicates more hot spotting of hits in your instance. Ideally you would have a close value between average_keyspace_hits and maximum_keyspace_hits, because this means that hits are more evenly distributed across your instance.

This principle applies to all metrics that have the average and maximum variations of the same metric.

Hot spotting example

If you compare average_keyspace_hits and maximum_keyspace_hits for all of the shards in your instance, comparing these values indicates where hot spotting occurs. For example, suppose shards in a 6-shard instance have the following number of hits:

• Shard 1 – 2 hits
• Shard 2 – 2 hits
• Shard 3 – 2 hits
• Shard 4 – 2 hits
• Shard 5 – 2 hits
• Shard 6 – 8 hits

In this example the average_keyspace_hits returns a value of 3, and the maximum_keyspace_hits returns 8, indicating that shard 6 is hot.