AWS Storage Gateway
/tldr: A hybrid storage service providing seamless, low-latency access to virtually unlimited cloud storage from your on-premises data center.
1. Core Concept & Infrastructure
The Storage Gateway is deployed as a **virtual appliance** (VMware, Hyper-V, KVM) or on a **dedicated hardware appliance** in your local data center. This gateway acts as a high-performance bridge, caching frequently accessed data locally while asynchronously transferring all data to AWS cloud storage.
Key Benefits
- **Local Performance:** Uses local disk for caching to provide low-latency access to data for on-premises applications.
- **Cost-Effective:** Leverages the scalability and low cost of Amazon S3 for long-term storage, reducing the need for expensive local infrastructure.
- **Security:** Data is encrypted both in transit (using SSL/TLS) and at rest in AWS.
- **Bandwidth Optimization:** Manages data transfer efficiently, only sending changed data blocks.
2. The Three Gateway Types
There are three main types of Storage Gateway, each offering a different interface to suit specific on-premises application needs:
File Gateway (NFS & SMB)
Provides a file-based interface (NFS v3/4.1 and SMB v2/3) for on-premises applications to store data as **objects in Amazon S3**. Each file share maps directly to an S3 bucket.
Use Case: Lift-and-shift of file shares, cloud-backed file storage, content repositories.
Volume Gateway (iSCSI)
Provides block storage to on-premises applications using the **iSCSI protocol**. Data is stored as volumes, which are backed by **EBS snapshots** in the cloud.
Use Case: Creating cloud-backed iSCSI volumes for local applications, disaster recovery, cloud migration planning.
- **Cached Volumes:** Keep frequently accessed data locally, less used data in AWS.
- **Stored Volumes:** Keep primary data locally, backup asynchronously to AWS.
Tape Gateway (VTL)
Provides a virtual tape library (VTL) interface to existing backup applications (e.g., NetBackup, Veeam). It replaces physical tapes with **virtual tapes** backed by **S3 and Glacier**.
Use Case: Offloading physical tape management, long-term archival, retiring on-premises tape infrastructure.
3. Key Differentiators
Summary of Data Flow
- **File Gateway:** Exposes NFS/SMB protocols. Stores data as S3 **Objects**.
- **Volume Gateway:** Exposes iSCSI protocol. Stores data as **EBS Snapshots**.
- **Tape Gateway:** Exposes VTL/iSCSI protocol. Stores data as S3/Glacier **Virtual Tapes**.
Storage Gateway simplifies the shift to hybrid cloud by giving your local applications a familiar face for cloud-based storage.