💽 Amazon EBS Multi-Attach
One shared volume. Multiple EC2 instances. Same-time read/write access.
Normally an EBS volume attaches to just one instance. Multi-Attach removes that limit — letting several EC2 instances connect to one volume at once, which is great for clustered, high-availability setups.
✅ Supported Volume Types
Only two volume types support this:
io1
io2
🚫 Not supported: gp2, gp3, st1, sc1
💡 Exam tip: See "Multi-Attach" → think io1 / io2, instantly.
⚙️ How It Works
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<h2>Availability Zone 1</h2>
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<span class="chip-label">EC2 Instance 1</span>
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<span class="chip-label">EC2 Instance 2</span>
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<span class="chip-label">EC2 Instance 3</span>
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<span class="vol-label">io2 volume with Multi-Attach</span>
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</div>One io1/io2 volume attaches to multiple EC2 instances
Every instance gets full read + write access
All instances access the data simultaneously
No duplicate copies — everyone shares the same storage
🎯 Common Use Cases
🖥️ Clustered Linux applications
📊 High-availability enterprise apps
🔄 Shared storage across multiple instances
💾 Concurrent read/write workloads (e.g. Teradata clusters)
⚠️ Key Limitations
📍 Same AZ only — no cross-AZ Multi-Attach
👥 Max 16 instances per volume
📂 Requires a cluster-aware file system to prevent data corruption
🧠 Exam Cheat Sheet
Rule | Value |
|---|---|
Supported types | io1, io2 |
Max instances | 16 |
AZ requirement | Same AZ only |
File system | Cluster-aware required |
Access | Full read + write, all instances |