Previous-generation EC2 families (such as m3, m4, c3, c4, t2, r3, and r4) often have modern equivalents with better price-performance. This finding flags running instances on those older families where Parsivex identifies a recommended replacement type.
This is different from oversized EC2 findings, which compare CPU utilization against the current instance size, and from idle EC2 findings, which flag near-zero utilization regardless of generation.
Before you change the instance type
- Verify the recommended modern type supports your required architecture (ARM vs x86), EBS optimization, and enhanced networking settings.
- Stop the instance before changing type unless you use a type that supports modification while stopped only — most generation jumps require a stop/start cycle.
- Test application compatibility in a non-production environment when moving across families (for example t2 to t3, or m4 to m6i).
- Update Auto Scaling launch templates, Terraform, or CloudFormation definitions so the instance is not reverted on the next deploy.
Paid plans include remediation scripts with stop, modify-instance-attribute, and start commands. Plan for brief downtime during the change.
What triggers this finding
A running EC2 instance on a previous-generation family (e.g. m3, m4, c3, c4, t2, r3, r4) where a modern equivalent instance type is available at lower cost.
Typical fix
Migrate to the recommended modern instance type. Stop the instance, change the type, then start and verify application compatibility.
Example savings
Often 10–30% of instance cost — varies by family and size.
See also: Severity and savings estimates for how Parsivex calculates figures on your report.