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Metrics Monitor Dashboards

This section contains a reference of dashboards available in Metrics Monitor.

MySQL Overview

This dashboard provides basic information about MySQL hosts.

Name Importance Description
MySQL Uptime INFO The amount of time since the MySQL server process was started.
Current QPS IMPORTANT

The number of queries executed by the server during the last second, including those executed within stored programs.

This variable does not include the following commands:

  • COM_PING
  • COM_STATISTICS
InnoDB Buffer Pool Size IMPORTANT Absolute value of the InnoDB buffer pool used for caching data and indexes in memory. This should be big enough to store the working set and never exceed the available memory on the database host.
Buffer Pool Size of Total RAM IMPORTANT Ratio between InnoDB buffer pool size and total memory. In most cases, the InnoDB buffer pool should be between 60% and 90% of available memory on a dedicated database host, but it depends on many factors.
MySQL Connections IMPORTANT

Max Connections is the maximum permitted number of simultaneous client connections. This is the value of the max_connections variable.

Max Used Connections is the maximum number of connections that have been in use simultaneously since the server was started.

Connections is the number of connection attempts (successful or not) to the MySQL server.

MySQL Active Threads INFO

Threads Connected is the number of open connections.

Threads Running is the number of threads not sleeping.

MySQL Questions INFO

The number of queries sent to the server by clients, excluding those executed within stored programs.

This variable does not count the following commands:

  • COM_PING
  • COM_STATISTICS
  • COM_STMT_PREPARE
  • COM_STMT_CLOSE
  • COM_STMT_RESET

MySQL Query Response Time

This dashboard provides information about query response time distribution.

Name Importance Description
Average Query Response Time INFO Average query response time is calculated as the total execution time of queries divided by the number of queries.
Query Response Time Distribution INFO Shows how many fast, neutral, and slow queries are executed per second.
Average Query Response Time (Read/Write Split) INFO Compare read and write query response time.
Read Query Response Time Distribution INFO Shows how many fast, neutral, and slow read queries are executed per second.
Write Query Response Time Distribution INFO Shows how many fast, neutral, and slow write queries are executed per second.

MongoDB Overview

This dashboard provides basic information about MongoDB instances.

Name Importance Description
Command Operations INFO

Shows how many times a command is executed per second on average during the selected interval.

Look for peaks and drops and correlate them with other graphs.

Connections IMPORTANT

Keep in mind the hard limit on the maximum number of connections set by your distribution.

Anything over 5,000 should be a concern, because the application may not close connections correctly.

Cursors INFO Helps identify why connections are increasing. Shows active cursors compared to cursors being automatically killed after 10 minutes due to an application not closing the connection.
Document Operations INFO When used in combination with Command Operations, this graph can help identify write aplification. For example, when one insert or update command actually inserts or updates hundreds, thousands, or even millions of documents.
Queued Operations CRITICAL Any number of queued operations for long periods of time is an indication of possible issues. Find the cause and fix it before requests get stuck in the queue.

getLastError Write Time

getLastError Write Operations

INFO This is useful for write-heavy workloads to understand how long it takes to verify writes and how many concurrent writes are occurring.
Asserts INFO Asserts are not important by themselves, but you can correlate spikes with other graphs.
Memory Faults CRITICAL Memory faults indicate that requests are processed from disk either because an index is missing or there is not enough memory for the data set. Consider increasing memory or sharding out.

MongoDB ReplSet

This dashboard provides information about replica sets and their members.

Name Importance Description
ReplSet State INFO Shows the role of the selected member instance (PRIMARY or SECONDARY)
ReplSet Members INFO Shows the number of members in the replica set
ReplSet Last Election INFO Shows how long ago the last election occurred
ReplSet Lag INFO Shows the current replication lag for the selected member
Storage Engine INFO Shows the storage engine used on the instance
Oplog Insert Time INFO

Shows how long it takes to write to the oplog. Without it the write will not be successful.

This is more useful in mixed replica sets (where instances run different storage engines).

Oplog Recovery Window CRITICAL

Shows the time range in the oplog and the oldest backed up operation.

For example, if you take backups every 24 hours, each one should contain at least 36 hours of backed up operations, giving you 12 hours of restore window.

Replication Lag INFO Shows the delay between an operation occurring on the primary and that same operation getting applied on the selected member
Elections INFO Elections happen when a primary becomes unavailable. Look at this graph over longer periods (weeks or months) to determine patterns and correlate elections with other events.
Member State Uptime INFO Shows how long various members were in PRIMARY and SECONDARY roles
Max Heartbeat Time IMPORTANT

Shows the heartbeat return times sent by the current member to other members in the replica set.

Long heartbeat times can indicate network issues or that the server is too busy.

Max Member Ping Time INFO This can show a correlation with the replication lag value

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