EBS, snapshots, AMIs, EFS and vertical scaling

Compare the options

EBS is not normally a shared network filesystem. Specialized multi-attach options have limitations and require cluster-aware software. EFS requires mount targets, security groups and NFS client access; do not expose NFS to arbitrary networks. An S3 prefix looks like a folder but does not supply normal POSIX filesystem semantics.

Snapshot and AMI lab

1. Create a marker file on a disposable EBS volume and flush application writes appropriately.
2. Create an EBS snapshot. Record the source volume, time and encryption key.
3. Restore it to a new volume in the target AZ, attach and verify the marker.
4. Create an AMI from a configured lab instance. Understand the reboot/no-reboot consistency tradeoff before choosing no-reboot.
5. Launch another instance from that AMI and verify the service, security groups and instance role separately. An AMI does not automatically duplicate every network or IAM setting.

Vertical scaling without losing the address

Use an Elastic IP for a stable public IPv4 when appropriate. Back up first, verify the target instance type supports the AMI architecture and required devices, stop the EBS-backed instance, change type and start. Expect downtime. An automatically assigned public address can change; the primary private IP generally persists. Confirm health and application performance after restart.

Performance

gp3 separates storage size from configurable IOPS/throughput within limits; provisioned performance still faces instance-level constraints. CPU-credit-based instances can have workload-dependent behaviour. Bigger does not guarantee faster if the bottleneck is a locked database or external API.

Verification and cleanup

Write down an actual restore test, not just a successful snapshot state. Deregistering an AMI may leave snapshots unless you intentionally remove eligible ones. Keep only recovery assets you need, and never delete a shared encryption key to save a small storage charge.

Official references

EBS snapshots EFS getting started Change EC2 instance type

Interview and revision check

What is the difference between an AMI and a running duplicate environment?

An AMI provides launchable image/block-device information. Network configuration, roles, secrets and dependent services still need separate setup.