Phase Verbs / Action Phrases
| Phrase | Meaning |
|---|---|
| attach (EBS to instance) | connect a network drive to an EC2 instance |
| detach (EBS from instance) | disconnect the drive, leaving data intact |
| provision (capacity) | pre-allocate a set size and IOPS before use |
| persist (data) | keep data across instance stops/restarts |
| terminate (instance with/without EBS) | depends on Delete on Termination setting |
Technical Vocabulary
| Term | Definition |
|---|---|
| EBS (Elastic Block Store) | Network-attached persistent block storage for EC2 instances |
| IOPS (I/O Operations Per Second) | A measure of storage performance — how many read/write operations per second |
| Provisioned capacity | You pre-define size (GB) and IOPS before using an EBS volume |
| Network drive | A drive that connects to an instance over the network, not physically |
| Block storage | Storage accessed in fixed-size “blocks”; like a hard drive (vs. object or file storage) |
| Delete on Termination | EC2 setting that controls whether an EBS volume is deleted when the instance is terminated |
| Root volume | The EBS volume containing the OS; the “C: drive” of an EC2 instance |
Key Concepts
What is EBS?
- Elastic Block Store = network-attached persistent storage
- Like a “network USB stick” — attach/detach from instances over the network
- Data persists even after the instance is stopped or terminated (if Delete on Termination is off)
- Can be re-attached to another instance in the same AZ after detachment
EBS Characteristics
| Property | Detail |
|---|---|
| Type | Network drive (not physically attached) |
| Latency | Slight network latency (vs. Instance Store) |
| AZ-bound | Must be in the same AZ as the EC2 instance |
| Attach limit | Usually 1 instance at a time (except io1/io2 Multi-Attach) |
| Billing | Based on provisioned capacity (GB + IOPS), not actual usage |
| Flexibility | Can be left unattached; attach/detach on demand |
EBS Availability Zone Constraint
- EBS volumes are locked to a specific AZ
- To use a volume in a different AZ → create a snapshot → restore in target AZ
Multiple EBS Volumes on One Instance
- One instance can have multiple EBS volumes (like multiple USB sticks in one machine)
- Each volume shows as a separate drive to the OS
Delete on Termination Attribute
| Volume | Default Behavior |
|---|---|
| Root volume | Deleted when instance is terminated (Delete on Termination = ON by default) |
| Additional EBS volumes | Kept after instance termination (Delete on Termination = OFF by default) |
- Can be changed in the console when launching an instance
- Exam scenario: “Save data on root volume after termination” → disable Delete on Termination
Exam Tips
- EBS = network-attached, AZ-scoped, persistent storage
- Root EBS: deleted on termination by default; additional volumes are NOT deleted by default
- Use snapshots to move volumes across AZs
- You pay for provisioned GB + IOPS, not what you actually use
- Can attach multiple EBS volumes to one instance; typically one volume per instance