Monitoring Amazon DocumentDB with CloudWatch
Amazon DocumentDB (with MongoDB compatibility) integrates with Amazon CloudWatch so that you can gather and analyze operational metrics for your clusters. You can monitor these metrics using the CloudWatch console, the Amazon DocumentDB console, the AWS Command Line Interface (AWS CLI), or the CloudWatch API.
CloudWatch also lets you set alarms so that you can be notified if a metric value breaches a threshold that you specify. You can even set up Amazon CloudWatch Events to take corrective action if a breach occurs. For more information about using CloudWatch and alarms, see the Amazon CloudWatch documentation.
Topics
Amazon DocumentDB metrics
To monitor the health and performance of your Amazon DocumentDB cluster and instances, you can view the following metrics in the Amazon DocumentDB console.
Note
Metrics in the following tables apply to both instance-based and elastic clusters.
Topics
Resource utilization metrics
Metric | Description |
---|---|
BackupRetentionPeriodStorageUsed |
The total amount of backup storage in GiB used to support
the point-in-time restore feature within the Amazon DocumentDB's
retention window. Included in the total reported by the
TotalBackupStorageBilled metric. Computed
separately for each Amazon DocumentDB cluster. |
ChangeStreamLogSize |
The amount of storage used by your cluster
to store the change stream log in megabytes. This value is
a subset of the total storage for the cluster
(VolumeBytesUsed ) and affects the cost of the
cluster. For storage pricing information, see the
Amazon DocumentDB product page |
CPUUtilization |
The percentage of CPU used by an instance. |
DatabaseConnections |
The number of connections open on an instance taken at a one-minute frequency. |
DatabaseConnectionsMax |
The maximum number of open database connections on an instance in a one-minute period. |
DatabaseCursors |
The number of cursors open on an instance taken at a one-minute frequency. |
DatabaseCursorsMax |
The maximum number of open cursors on an instance in a one-minute period. |
DatabaseCursorsTimedOut |
The number of cursors that timed out in a one-minute period. |
FreeableMemory |
The amount of available random access memory, in bytes. |
FreeLocalStorage |
This metric reports the amount of storage available to each instance for temporary tables and logs. This value depends on the instance class. You can increase the amount of free storage space for an instance by choosing a larger instance class for your instance. |
LowMemThrottleQueueDepth |
The queue depth for requests that are throttled due to low available memory taken at a one-minute frequency. |
LowMemThrottleMaxQueueDepth |
The maximum queue depth for requests that are throttled due to low available memory in a one-minute period. |
LowMemNumOperationsThrottled |
The number of requests that are throttled due to low available memory in a one-minute period. |
SnapshotStorageUsed |
The total amount of backup storage in GiB
consumed by all snapshots for a given Amazon DocumentDB cluster
outside its backup retention window. Included in the total
reported by the TotalBackupStorageBilled metric.
Computed separately for each Amazon DocumentDB cluster. |
SwapUsage |
The amount of swap space used on the instance. |
TotalBackupStorageBilled |
The total amount of backup storage in GiB for which you are billed for a given Amazon DocumentDB cluster. Includes the backup storage measured by the BackupRetentionPeriodStorageUsed and SnapshotStorageUsed metrics. Computed separately
for each Amazon DocumentDB cluster. |
TransactionsOpen |
The number of transactions open on an instance taken at a one-minute frequency. |
TransactionsOpenMax |
The maximum number of transactions open on an instance in a one-minute period. |
VolumeBytesUsed |
The amount of storage used by your cluster
in bytes. This value affects the cost of the cluster. For
pricing information, see the
Amazon DocumentDB product page |
Latency metrics
Metric | Description |
---|---|
DBClusterReplicaLagMaximum |
The maximum amount of lag, in milliseconds, between the primary instance and each Amazon DocumentDB instance in the cluster. |
DBClusterReplicaLagMinimum |
The minimum amount of lag, in milliseconds, between the primary instance and each replica instance in the cluster. |
DBInstanceReplicaLag |
The amount of lag, in milliseconds, when replicating updates from the primary instance to a replica instance. |
ReadLatency |
The average amount of time taken per disk I/O operation. |
WriteLatency |
The average amount of time, in milliseconds, taken per disk I/O operation. |
Operations metrics
Metric | Description |
---|---|
DocumentsDeleted |
The number of deleted documents in a one-minute period. |
DocumentsInserted |
The number of inserted documents in a one-minute period. |
DocumentsReturned |
The number of returned documents in a one-minute period. |
DocumentsUpdated |
The number of updated documents in a one-minute period. |
OpcountersCommand |
The number of commands issued in a one-minute period. |
OpcountersDelete |
The number of delete operations issued in a one-minute period. |
OpcountersGetmore |
The number of getmores issued in a one-minute period. |
OpcountersInsert |
The number of insert operations issued in a one-minute period. |
OpcountersQuery |
The number of queries issued in a one-minute period. |
OpcountersUpdate |
The number of update operations issued in a one-minute period. |
TransactionsStarted |
The number of transactions started on an instance in a one-minute period. |
TransactionsCommitted |
The number of transactions committed on an instance in a one-minute period. |
TransactionsAborted |
The number of transactions aborted on an instance in a one-minute period. |
TTLDeletedDocuments |
The number of documents deleted by a TTLMonitor in a one-minute period. |
Throughput metrics
Metric | Description |
---|---|
NetworkReceiveThroughput |
The amount of network throughput, in bytes per second, received from clients by each instance in the cluster. This throughput doesn't include network traffic between instances in the cluster and the cluster volume. |
NetworkThroughput |
The amount of network throughput, in bytes per second, both received from and transmitted to clients by each instance in the Amazon DocumentDB cluster. This throughput doesn't include network traffic between instances in the cluster and the cluster volume. |
NetworkTransmitThroughput |
The amount of network throughput, in bytes per second, sent to clients by each instance in the cluster. This throughput doesn't include network traffic between instances in the cluster and the cluster volume. |
ReadIOPS |
The average number of disk read I/O operations per second. Amazon DocumentDB reports read and write IOPS separately, and on one-minute intervals. |
ReadThroughput |
The average number of bytes read from disk per second. |
StorageNetworkReceiveThroughput |
The amount of network throughput, in bytes per second, received from the Amazon DocumentDB cluster storage volume by each instance in the cluster. |
StorageNetworkTransmitThroughput |
The amount of network throughput, in bytes per second, sent to the Amazon DocumentDB cluster storage volume by each instance in the cluster. |
StorageNetworkThroughput |
The amount of network throughput, in bytes per second, received and sent to the Amazon DocumentDB cluster storage volume by each instance in the Amazon DocumentDB cluster. |
VolumeReadIOPs |
The average number of billed read I/O operations from a cluster volume, reported at 5-minute intervals. Billed read operations are calculated at the cluster volume level, aggregated from all instances in the cluster, and then reported at 5-minute intervals. The value is calculated by taking the value of the read operations metric over a 5-minute period. You can determine the amount of billed read operations per second by taking the value of the billed read operations metric and dividing by 300 seconds. For example, if the You accrue billed read operations for queries that request database pages that are not present in the buffer cache and therefore must be loaded from storage. You might see spikes in billed read operations as query results are read from storage and then loaded into the buffer cache. |
VolumeWriteIOPs |
The average number of billed write I/O operations from a cluster volume, reported at 5-minute intervals. Billed write operations are calculated at the cluster volume level, aggregated from all instances in the cluster, and then reported at 5-minute intervals. The value is calculated by taking the value of the write operations metric over a 5-minute period. You can determine the amount of billed write operations per second by taking the value of the billed write operations metric and dividing by 300 seconds. For example, if the Note that |
WriteIOPS |
The average number of disk write I/O operations per second. When used on a cluster level, WriteIOPs are evaluated across all instances in the cluster. Read and write IOPS are reported separately, on 1-minute intervals. |
WriteThroughput |
The average number of bytes written to disk per second. |
System metrics
Metric | Description |
---|---|
BufferCacheHitRatio |
The percentage of requests that are served by the buffer cache. |
DiskQueueDepth |
the number of concurrent write requests to the distributed storage volume. |
EngineUptime |
The amount of time, in seconds, that the instance has been running. |
IndexBufferCacheHitRatio |
The percentage of index requests that are served by the buffer cache. You might see a spike greather than 100% for the metric right after you drop an index, collection or database. This will automatically be corrected after 60 seconds. This limitation will be fixed in a future patch update. |
T3 instance metrics
Metric | Description |
---|---|
CPUCreditUsage |
The number of CPU credits spent during the measurement period. |
CPUCreditBalance |
The number of CPU credits that an instance has accrued. This balance is depleted when the CPU bursts and CPU credits are spent more quickly than they are earned. |
CPUSurplusCreditBalance |
The number of surplus CPU credits spent to sustain CPU performance when the CPUCreditBalance value is zero. |
CPUSurplusCreditsCharged |
The number of surplus CPU credits exceeding the maximum number of CPU credits that can be earned in a 24-hour period, and thus attracting an additional charge. For more information, see Monitoring your CPU credits. |
Viewing CloudWatch data
You can view Amazon CloudWatch data using the CloudWatch console, the Amazon DocumentDB console, AWS Command Line Interface (AWS CLI), or the CloudWatch API.
Amazon DocumentDB dimensions
The metrics for Amazon DocumentDB are qualified by the values for the account or operation. You can use the CloudWatch console to retrieve Amazon DocumentDB data filtered by any of the dimensions in the following table.
Dimension | Description |
---|---|
DBClusterIdentifier |
Filters the data that you request for a specific Amazon DocumentDB cluster. |
DBClusterIdentifier, Role |
Filters the data that you request for a specific Amazon DocumentDB cluster, aggregating the metric by instance role (WRITER/READER). For example, you can aggregate metrics for all READER instances that belong to a cluster. |
DBInstanceIdentifier |
Filters the data that you request for a specific database instance. |
Monitoring Opcounter metrics
Opcounter metrics have a non-zero value (usually ~50) for idle clusters. This is because Amazon DocumentDB performs periodic health checks, internal operations, and metrics collection tasks.
Monitoring database connections
When you view the number of connections by using database engine
commands such as db.runCommand( { serverStatus: 1 })
, you
might see up to 10 more connections than you see in
DatabaseConnections
through CloudWatch.
This occurs because Amazon DocumentDB performs periodic health checks and metrics
collection tasks that don't get accounted for in DatabaseConnections
.
DatabaseConnections
represents customer-initiated
connections only.