Review Available Metrics¶
You can review the following metrics to monitor your database deployments. All hardware metrics include metrics or individual charts for maximum values.
The metrics available depend on your user role and database deployment type.
Currently, serverless instance metrics don't support any third-party monitoring services (for example, Datadog).
Metric | Description |
---|---|
Asserts | Displays the following information:
Monitor asserts to track how many errors occur while trying to read or write data. Check the server logs to identify the source of any errors. |
Avg Object Size | Displays the average object size across all collections in the database. Monitor object size to track the size of your objects and better understand your database space. |
Cache Activity | Displays the following information:
Monitor the MongDB cache, which stores frequently accessed data in memory to service queries faster. |
Cache Usage | Displays the following information:
These metrics include both indexes and data from the working set. Sustained high cache usage indicates the RAM is too small for your workloads. Optimize your queries to avoid frequent disk reads. If write operations make cache usage high, throttle them. |
Collections | Displays the number of collections in the database. Monitor collections to determine restart times, continuous backup performance, and stability. |
Connections (serverless instance/replica set) or
connection (sharded cluster) | Displays the total number of active connections to the database deployment. Monitor connections to determine whether the current connection limits are sufficient. If necessary, upgrade the cluster tier. |
Cursors | Displays the following information:
Monitor cursors to close unnecessary cursors and reduce the timeout configuration in the application. |
DB Storage | Displays the following information:
Monitor storage space to determine whether to use disk auto-scaling or manually increase the disk size. You can also monitor this metric to verify backup billing. |
Disk IOPS | Displays input operations per second. Monitor whether disk IOPS approaches the maximum provisioned IOPS. Determine whether the cluster can handle future workloads. |
Disk Latency | Displays the following information:
Monitor disk latency to track the efficiency of reading from and writing to disk. |
Disk Queue Depth | Displays the average length of the queue of requests issued to the disk partition that MongoDB uses. Monitor disk queue depth to identify potential issues and bottlenecks. |
Disk Space Free | Displays the total amount of free space remaining on disk. Monitor free disk space to determine whether to use disk auto-scaling or manually increase the disk size. |
Disk Space Percent Free | Displays the total amount of free space remaining on disk as a percentage of the total disk space. Monitor the percentage of free disk space to determine whether to use disk auto-scaling or manually increase the disk size. |
Disk Space Used | Displays the total space on disk used. Monitor the used disk space to determine whether to use disk auto-scaling or manually increase the disk size. |
Document Metrics | Displays the following information:
Monitor document metrics to measure the work MongoDB completes. |
Execution Time | Displays the average time in seconds for the following metrics:
Monitor execution time for an increase in read operations to optimize queries and indexes. |
Index Size | Displays the total size of all indexes in the database. This metric includes the overhead incurred by indexes on top of the actual document data on which the indexes are based. Monitor the index size to manage your indexes. To learn more, see Indexing Strategies. |
Indexes | Displays the total number of indexes in the database. Monitor indexes to manage them. To learn more, see Indexing Strategies. |
Locks | Displays the following information:
Monitor locks to optimize queries. |
Max Normalized System CPU | Displays the maximum CPU usage values of all processes on the node, scaled to a range of 0-100% by dividing by the number of CPU cores. Monitor CPU usage to determine whether data is retrieved from disk instead of memory. |
Max System CPU | Displays the maximum CPU usage values of all processes on the node. Monitor CPU usage to determine whether data is retrieved from disk instead of memory. |
Max System Memory | Displays the maximum system memory values in bytes. Monitor memory to determine whether to upgrade to a higher cluster tier. |
Memory | Displays the total consumption of memory in megabytes at a particular point in time:
Monitor memory to determine whether to upgrade to a higher cluster tier. |
Network | Displays the following information:
|
Normalized Process CPU | Displays the following information:
Monitor CPU usage to determine whether data is retrieved from disk instead of memory. |
Normalized System CPU | Displays the CPU usage of all processes on the node, scaled to a range of 0-100% by dividing by the number of CPU cores. Monitor CPU usage to determine whether data is retrieved from disk instead of memory. |
Num Extent | Displays the total number of contiguously allocated chunks of data file space for the database. Monitor this metric to better understand your database space. |
Objects | Displays the number of objects in the database. Monitor this metric to better understand your database space. |
OpCounters | Displays the number of the following operations per second run on a MongoDB process since the process last started:
Monitor MongoDB operations to validate performance issues related to high workloads. Confirm the type of operations responsible for the load. |
OpCounters - Repl | Displays the following information:
Monitor MongoDB operations to validate performance issues related to high workloads. Confirm the type of operations responsible for the load. |
Operation Execution Time | Displays the average time in milliseconds to execute the following operations:
Monitor execution time for an increase in read operations to optimize queries and indexes. Determine whether you need to upgrade your cluster tier. |
Oplog GB/Hour | Displays the average rate in gigabytes of oplog data that the primary generates per hour. Monitor oplog data to determine whether you have to increase the oplog size. |
Page Faults | Displays the average rate of page faults on this process per second over the selected sample period. In non-Windows environments this applies to hard page faults only. Monitor page faults to determine whether to increase your memory. |
Process CPU | Displays the following information:
Monitor CPU usage to determine whether data is retrieved from disk instead of memory. |
Query Executor | Displays the following information:
Monitor the query executor to determine whether you have any inefficient queries. |
Query Targeting | Displays the efficiency of read operations run on MongoDB:
Monitor query targeting to determine read efficiency and optimize queries and indexes. |
Replication Headroom | Displays the difference between the primary's replication oplog window and the secondary's replication lag. Monitor replication headroom to determine whether the secondary might fall off the oplog. |
Replication Lag | Displays the approximate number of seconds the secondary is behind the primary in write application. Monitor replication lag to determine whether the secondary might fall off the oplog. |
Scan and Order | Displays the number of operations per second returning results that required a sort in-memory. Monitor this metric to identify whether your queries need indexes. |
System CPU | Displays the CPU usage of all processes on the node. |
System Memory | Displays the following information:
Monitor memory to determine whether to upgrade to a higher cluster tier. |
Tickets Available | Displays the following information:
Monitor the tickets available to see when read and write requests queue. |
Util % | Displays the percentage of time that requests are issued to and serviced by disk. This metric includes requests from any process, not just MongoDB processes. Monitor whether utilization is high. Determine whether to increase the provisioned IOPS or upgrade the cluster. |
Views | Displays the number of views in the database. Monitor views to help optimize your database. |