RDS Cloudwatch metrics: monitor your RDS instances | Padok

RDS Instance Type - General purpose and Memory optimized

All the AWS database service RDS instances types come up with varying combinations of CPU, memory, storage, and networking capacity. Finding the best database instance type might be a bit tricky if you don’t know them and for what use.

• “General purpose database instances provide a balance of compute, memory and networking resources, and can be used for a variety of diverse workloads”. It’s a good choice for many database workloads including small and mid-size databases.

You might also look for the latest generation of General Purpose Instance:

• “Memory optimized instances are designed to deliver fast performance for workloads that process large data sets in memory”. It’s a good choice for memory-intensive database workloads at a larger scale.

You might also look for the latest generation of Memory Optimized Instance:

AWS RDS Instance Features

For each of your AWS RDS Instances, you might want to wrap some metrics around the following topic:

• CPU / RAM consumption
• Network traffic
• Disk space consumption
• Database connections
• IOPS metrics

Let’s dig into it!

CPU / RAM consumption

For your RDS instance:

For your RDS burstable performance instances:

Network traffic CloudWatch Metrics

Disk Space Consumption CloudWatch Metrics

Database connections CloudWatch Metrics

IOPS CloudWatch Metrics

Going deeper, the enhanced monitoring: Monitor your processes

Launched in 2016, RDS Enhanced Monitoring is a feature that enables customers to send amazon rds metrics to cloudwatch from their database server’s operating system. It allows you to get some RDS server performance insights.

By default, CloudWatch gathers metrics about CPU utilization from the hypervisor when Enhanced Monitoring gathers its metrics from an agent directly on the instance. Enhanced Monitoring is particularly useful when you want to see how different processes or threads on your DB instance use the CPU.

You can enable this option directly on your DB instance when:

1. You create a DB → In the Configure Advanced Settings page (with the amazon rds console) or through parameters (with terraform)
2. You create a Read Replica → In the Configure Advanced Settings page (in aws console) or through your terraform code (through a parameter).
3. You modify a DB Instance → In the Modify DB Instance page or through your terraform code (which will update your DB).

For your Enhanced Monitoring you’ll need:

1. Set the Monitoring Role property to the IAM role that you created to permit Amazon RDS to communicate with CloudWatch for you (or either choose Default to have RDS create this role for you)
2. Set the Granularity property to the interval chosen (1, 5, 10, 15, 30 or 60 seconds)

Enabling enhanced monitoring will show the following Process list on your RDS instance:

• RDS child processes - A summary of RDS processes that support the DB instance. 
• RDS processes - A summary of the resources used by the RDS management agent, diagnostics monitoring processes and other AWS processes that are required to support RDS DB instances.
• OS processes -A summary of the kernel and system processes (which have a low impact on performance).

It is also available through CloudWatch, through the Logs section in the navigation pane, you need to select RDSOSMetrics from the list of log groups and then select your desired log stream. It’s based on the following groups:

• general - Global information about the DB instance.
• cpuUtilization - CPU and its uses by the DB instance logs.
• fileSys - File-system logs.
• loadAverageMinute - Number of processes requesting CPU time.
• memory - Memory logs
• network - Network interface and bytes received/uploaded logs
• processList - CPU, memory used by the processes logs
• swap - Swap memory logs
• tasks - Tasks logs

Find more information about EC2 CloudWatch Metrics and EBS CloudWatch metrics in those two blog posts.

You may check what is best for your workflow now that you understand better RDS types, and which metrics are important to monitor.