Phase Verbs / Action Phrases
| Phrase | Meaning |
|---|---|
| provision (IOPS) | pre-allocate a guaranteed number of I/O operations per second |
| burst (IOPS) | temporarily exceed baseline IOPS for short periods |
| scale (throughput independently) | gp3 allows increasing throughput without changing volume size |
| optimize (for throughput vs. IOPS) | choose the right volume type based on workload pattern |
Technical Vocabulary
| Term | Definition |
|---|---|
| IOPS | I/O Operations Per Second — measure of storage read/write speed |
| Throughput | Data transfer rate (MB/s) — how much data moves per second |
| SSD | Solid State Drive — fast, IOPS-oriented storage |
| HDD | Hard Disk Drive — spinning disk; cheaper, throughput-oriented |
| gp3 / gp2 | General Purpose SSD — balanced performance for most workloads |
| io1 / io2 | Provisioned IOPS SSD — guaranteed IOPS for critical/database workloads |
| st1 | Throughput Optimized HDD — cheap + high throughput for big data |
| sc1 | Cold HDD — cheapest; for infrequently accessed data |
| Nitro EC2 | EC2 instances with next-gen hypervisor; needed for >32,000 IOPS on io1/io2 |
| Boot volume | The EBS volume the OS boots from; only SSD types (gp2, gp3, io1, io2) are supported |
Key Concepts
EBS Volume Types Summary
| Type | Media | Max IOPS | Max Throughput | Boot? | Best For |
|---|---|---|---|---|---|
| gp3 | SSD | 16,000 | 1,000 MB/s | ✅ | General workloads, dev/test, most databases |
| gp2 | SSD | 16,000 | 250 MB/s | ✅ | Same as gp3; older generation |
| io1 | SSD | 64,000 (Nitro) | 1,000 MB/s | ✅ | Critical DBs needing >16,000 IOPS |
| io2 Block Express | SSD | 256,000 | — | ✅ | Ultra-high performance, sub-ms latency |
| st1 | HDD | 500 | 500 MB/s | ❌ | Big data, data warehousing, log processing |
| sc1 | HDD | 250 | 250 MB/s | ❌ | Cold/archived data, lowest cost |
General Purpose SSD (gp2 vs gp3)
| gp3 | gp2 | |
|---|---|---|
| Baseline IOPS | 3,000 | 3,000 (burst) |
| Max IOPS | 16,000 | 16,000 |
| IOPS scaling | Independent of size | Linked to size (3 IOPS/GB) |
| Max throughput | 1,000 MB/s | 250 MB/s |
| Recommendation | Prefer gp3 (newer, more flexible) | Legacy |
Provisioned IOPS SSD (io1 vs io2)
- Use when you need > 16,000 IOPS (beyond gp3 max)
- For mission-critical workloads: databases, high-performance applications
- io1: Max 64,000 IOPS on Nitro / 32,000 on others; ratio ~50:1 (IOPS:GB)
- io2 Block Express: Max 256,000 IOPS; sub-ms latency; ratio 1,000:1
- Both io1 and io2 support Multi-Attach (one volume → multiple instances)
HDD Volumes (st1, sc1)
- Cannot be used as boot volumes
- Max size: 16 TB
- st1 (Throughput Optimized HDD): 500 IOPS, 500 MB/s — for Kafka, big data, Hadoop
- sc1 (Cold HDD): 250 IOPS, 250 MB/s — cheapest — for archival data
Exam Tips
- Only SSD types (gp2, gp3, io1, io2) can be boot volumes — HDD (st1, sc1) cannot
- gp3 > gp2 in every way — prefer gp3 for new workloads
- Need IOPS > 32,000 → io1/io2 with Nitro EC2
- Need high throughput at low cost (Hadoop, Kafka) → st1
- Infrequent access / cheapest → sc1
- gp3: IOPS and throughput configurable independently of size
- gp2: IOPS and size are linked (3 IOPS per GB, max 16,000)