EC2 Hibernate – In-Depth Overview | Notion

What is EC2 Hibernate

EC2 Hibernate allows you to pause and resume your Amazon EC2 instance by saving the contents of its RAM (memory) to the root volume (EBS) before shutting down.
When restarted, the instance resumes exactly where it left off, similar to putting a laptop into sleep/hibernate mode.

How EC2 Hibernate Works

When hibernation is initiated:
- The RAM contents (running processes, in-memory data) are saved to the EBS root volume.
- The instance’s EBS volumes remain attached.
- The instance ID, private IP, and Elastic IP (if any) remain the same.
When you start the instance again:
- The RAM state is restored from EBS, and processes continue from the point they stopped.

Key Characteristics

Feature	Description
Instance Type	Supported for certain instance families (e.g., C3, C4, M3, M4, R3, R4, T2, T3, etc.).
Root Volume	Must be EBS-backed and encrypted to store the RAM snapshot.
RAM Size Limit	Instances with less than 150 GB RAM are supported.
OS Support	Linux and Windows AMIs that support hibernation.
Instance State	Transitions from running → stopped (not terminated).

Benefits of EC2 Hibernate

Fast Boot Time
- Resume workloads immediately without reloading applications.
State Preservation
- Keeps in-memory data, sessions, and cached content.
Cost Efficiency
- Pay only for EBS storage while the instance is hibernated, not for compute.
Useful for Development or Batch Jobs
- Ideal for temporary workloads, data analysis, or periodic jobs where you need the same session context.

Requirements for EC2 Hibernate

Requirement	Description
EBS-backed Instance	Root volume must be EBS-backed (not instance store).
Encrypted Root Volume	Required to protect memory snapshot.
Sufficient EBS Size	The root volume must be large enough to store RAM data.
Supported Instance Type	Not all types support hibernation.
Enabled at Launch	Hibernation must be enabled during instance creation (cannot enable later).