AWS - EBS Vs Instance Store

 Amazon EBS (Elastic Block Store)

• Type: Network-attached, persistent block storage.

• Persistence: Data persists even if the EC2 instance stops, hibernates, or terminates (unless you set DeleteOnTermination=true).

• Durability: Replicated automatically within the same AZ.

• Performance options:

  • SSD-backed (gp3, io1, io2) → great for transactional workloads.

  • HDD-backed (st1, sc1) → for big, sequential workloads.

• Features:

  • Snapshots to S3 (backup/restore, AMI creation).

  • Encryption at rest and in transit.

  • Resizable volumes, change type without downtime.

• Use cases:

  • Databases, critical apps, persistent storage.

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Instance Store (Ephemeral Storage)

• Type: Physically attached NVMe or SSD disks to the EC2 host.

• Persistence: Data is ephemeral → lost when:

  • Instance stops, hibernates, or terminates.

  • Underlying hardware fails.

• Durability: No replication across hardware.

• Performance: Very high IOPS and low latency (because it’s directly attached).

• Features:

  • No snapshots, no encryption by default.

  • Size/type depends on instance family (e.g., i3, d2, m5d).

• Use cases:

  • Cache, buffers, temporary storage, high-speed scratch data.

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Key Differences (EBS vs Instance Store)

Feature	Amazon EBS	Instance Store
Persistence	Persists after stop/terminate	Data lost on stop/terminate
Attachment	Network-attached (can detach/attach)	Physically attached to host
Durability	Replicated in AZ (fault-tolerant)	No replication, tied to hardware
Resizing	Can resize, change volume type	Fixed size (depends on instance)
Snapshots	Supported (S3 backup)	Not supported
Performance	High, but via network	Extremely high, local
Encryption	Supported	Not supported (must do at app level)
Best for	Databases, persistent workloads	Cache, temp files, high-speed scratch