Tech Study DeckTechnical study guides and structured courses
Menu

AWS Systems Architect Professional

AWS Storage Gateway: File, Volume, and Tape Modes – SAP-C02 Study Guide

Learn AWS Storage Gateway architecture, File Gateway, Volume Gateway modes, Tape Gateway, protocols, caching, backups, and SAP-C02 exam decision points.

AWS Systems Architect ProfessionalAWS Systems Architect ProfessionalUpdated Sep 1, 2026
Study options
WatchComing later
ListenComing later
ReadAvailable
ReviewComing later

Study guide

Technical reference and lesson notes

Purpose of This Lesson

AWS Storage Gateway provides hybrid storage integration between on-premises environments and AWS. A gateway appliance runs in the data center or another supported environment, exposing familiar storage protocols to local applications while storing or backing up data in AWS services such as Amazon S3, Amazon EBS, S3 Glacier, and S3 Glacier Deep Archive.

The central exam skill is selecting the correct gateway type and storage mode based on the required protocol, local data-access needs, and AWS storage destination.

Key Concepts

Storage Gateway Architecture

A Storage Gateway can be deployed as a virtual appliance on supported platforms such as:

  • VMware
  • Microsoft Hyper-V
  • KVM
  • Amazon EC2
  • A dedicated hardware appliance

The gateway presents a local storage interface to applications and transfers data to AWS over an encrypted connection. The correct gateway depends primarily on whether the application requires a file, block, or virtual tape interface.

Gateway typeClient protocol or interfacePrimary AWS storageTypical purpose
File GatewayNFS or SMBAmazon S3Provide a file share backed by S3 objects
Volume GatewayiSCSI block storageAmazon S3, with EBS snapshots for stored volumesExtend or back up block storage
Tape GatewayVirtual tape libraryAmazon S3, S3 Glacier, or S3 Glacier Deep ArchiveReplace or supplement physical tape infrastructure

File Gateway

File Gateway presents an on-premises file share through NFS or SMB. Applications continue to use file-system semantics, while the gateway stores files as objects in Amazon S3.

Important characteristics include:

  • A local cache provides low-latency access to recently used data.
  • Files are stored as S3 objects on the AWS side.
  • S3 storage classes can be used to match access frequency and cost requirements.
  • It can support on-premises applications and EC2-based workloads that require file access to S3-backed data.
  • It is appropriate when the application expects a file system but the durable backend should be object storage.

File Gateway is not an iSCSI block-storage solution. If the application requires block devices, select Volume Gateway instead.

Volume Gateway

Volume Gateway exposes block storage through iSCSI. It has two operating modes with different data-placement and availability characteristics.

#### Cached Volume Mode

With cached volumes:

  • The complete data set is stored in Amazon S3.
  • Frequently accessed or recently accessed data is cached locally.
  • Local storage requirements are reduced compared with keeping the entire data set on premises.
  • Applications use iSCSI block volumes rather than NFS or SMB file shares.

Cached volumes are a good fit when AWS should hold the authoritative data set while local workloads still need low-latency access to an active working set.

#### Stored Volume Mode

With stored volumes:

  • The complete data set is maintained on premises.
  • Data is asynchronously backed up to Amazon S3.
  • Point-in-time backups are represented through Amazon EBS snapshots.
  • Local access remains primary, while AWS provides durable backup and recovery capabilities.

Stored volumes are more appropriate when the complete data set must remain locally available for performance, operational, or connectivity reasons, but the organization also needs AWS-based backup and point-in-time recovery.

Tape Gateway

Tape Gateway provides a virtual tape library for existing backup applications. Backup servers interact with virtual media, a media changer, and virtual tape drives as though they were using a physical tape environment.

Key characteristics include:

  • Designed for backup applications that support virtual tape libraries.
  • Virtual tapes are initially written to Amazon S3.
  • Ejected tapes can be archived in S3 Glacier or S3 Glacier Deep Archive.
  • Backup tools such as NetBackup, Backup Exec, and Veeam can integrate with the gateway.
  • Virtual tape sizes must be selected when configuring the tapes.
  • The gateway supports up to 1,500 virtual tapes with a maximum total capacity of 1 PB.
  • Data is encrypted in transit using SSL and protected on the server side with SSE-S3.

Tape Gateway is primarily a compatibility and backup-migration solution. It allows organizations to retain existing tape-oriented processes while moving the underlying storage toward AWS.

Architecture Decision Guide

RequirementRecommended choiceWhy
Existing application requires NFS or SMBFile GatewayPresents a file share while storing files as S3 objects
Application requires iSCSI block volumes and AWS should hold the full data setVolume Gateway with cached volumesKeeps the full data set in S3 and caches active data locally
Application requires iSCSI block volumes and the full data set must remain on premisesVolume Gateway with stored volumesMaintains local data and asynchronously backs it up to S3
Existing backup workflow depends on virtual or physical tape conceptsTape GatewayProvides virtual tapes compatible with supported backup software
Need object storage directly from an applicationUse Amazon S3 directly when possibleStorage Gateway is useful when the application requires a traditional file, block, or tape interface

Exam-Relevant Takeaways

  • File Gateway uses NFS or SMB and stores file data as Amazon S3 objects.
  • Volume Gateway uses iSCSI and provides block storage, not file shares.
  • Cached Volume mode: the full data set is in S3; frequently accessed data is cached locally.
  • Stored Volume mode: the full data set is local; asynchronous backups are sent to S3 and point-in-time EBS snapshots are created.
  • Tape Gateway supports virtual tape libraries and moves archived tapes to S3 Glacier or S3 Glacier Deep Archive.
  • Storage Gateway is useful when an existing application cannot directly use S3 but still needs access to AWS-backed storage.
  • Local caching improves access to recently used data but does not eliminate the need to plan local cache capacity and connectivity.
  • Select the gateway based on the application’s required storage protocol first, then choose the data-placement mode.

Common Exam Traps

  • Confusing File Gateway with Volume Gateway: NFS and SMB indicate File Gateway; iSCSI indicates Volume Gateway.
  • Reversing cached and stored volumes: Cached volumes keep the complete data set in S3 and cache active data locally. Stored volumes keep the complete data set locally and back it up to S3.
  • Assuming File Gateway stores files in EBS: File Gateway stores data as S3 objects, not EBS volumes.
  • Assuming Tape Gateway archives directly to Glacier: Tape data is written to S3 first; tapes can then be archived to S3 Glacier or S3 Glacier Deep Archive after ejection.
  • Treating Storage Gateway as a generic file server: The gateway is valuable because it bridges traditional protocols to AWS storage. The selected protocol and backend behavior still matter.
  • Ignoring application compatibility: Tape Gateway requires compatible backup software and virtual tape-library integration.
  • Assuming caching replaces durable storage: The local cache is an access-performance feature. Durable placement depends on the selected gateway mode and AWS service.

Real-World Engineer Notes

  • Verify that the gateway host has enough local storage for its cache or stored-volume data requirements.
  • Plan network connectivity carefully. Gateway operations depend on reliable communication with AWS, while local cache behavior determines how well workloads tolerate temporary connectivity issues.
  • Use File Gateway when an application cannot be modified to call S3 APIs but can use NFS or SMB.
  • Use Volume Gateway when the workload requires a block device and cannot consume a file share.
  • Stored volumes are useful when local access is operationally important, but they should not be confused with a multi-site synchronous replica.
  • For backup modernization, Tape Gateway can reduce the need to redesign established backup jobs while enabling AWS archival tiers.
  • Encryption in transit and server-side encryption protect transferred and stored data, but access control, network routing, and backup retention still require separate design decisions.

Quick Reference Summary

  • File Gateway: NFS/SMB to S3; local cache; file interface backed by objects.
  • Volume Gateway: iSCSI block interface.
  • Cached Volume: full data set in S3, active data cached locally.
  • Stored Volume: full data set locally, asynchronous S3 backup, point-in-time EBS snapshots.
  • Tape Gateway: virtual tape library; S3 for active virtual tapes; Glacier or Deep Archive for archived tapes.
  • Selection rule: choose based on file, block, or tape requirements, then select the appropriate data-placement mode.

Flashcards

  1. Q: What problem does AWS Storage Gateway solve?

A: It connects on-premises applications and storage protocols to AWS-backed storage services.

  1. Q: Which protocols does File Gateway expose?

A: NFS and SMB.

  1. Q: How does File Gateway represent data in AWS?

A: Files are stored as objects in Amazon S3.

  1. Q: Which protocol does Volume Gateway use?

A: iSCSI.

  1. Q: What is the data placement model for cached volumes?

A: The full data set is stored in S3, while frequently accessed data is cached locally.

  1. Q: What is the data placement model for stored volumes?

A: The full data set remains on premises and is asynchronously backed up to S3.

  1. Q: What AWS backup artifacts are associated with stored volumes?

A: Point-in-time Amazon EBS snapshots.

  1. Q: What is the primary use case for Tape Gateway?

A: Providing a virtual tape library for existing backup applications.

  1. Q: Where are virtual tapes initially stored?

A: Amazon S3.

  1. Q: Which archive tiers can be used after tapes are ejected?

A: S3 Glacier or S3 Glacier Deep Archive.

  1. Q: Which gateway should be selected for an application requiring a traditional file share backed by S3?

A: File Gateway.

  1. Q: Which gateway should be selected for an application requiring block-level iSCSI access?

A: Volume Gateway.

Practice Questions

Question 1

A company has an on-premises application that can access only SMB file shares. The company wants files to be stored durably in Amazon S3 while frequently accessed content remains available with low latency on premises. Which solution meets the requirements?

A. Volume Gateway in stored volume mode
B. File Gateway with a local cache
C. Tape Gateway with S3 Glacier
D. Amazon EBS Multi-Attach volumes

Correct answer: B. File Gateway with a local cache

Explanation: File Gateway exposes SMB and stores files as S3 objects. Its local cache provides low-latency access to recently used content. Volume Gateway uses iSCSI block storage and does not provide an SMB file share.

Question 2

A legacy database requires block-level storage through iSCSI. The complete data set must remain on premises for local performance, but the company requires asynchronous AWS backups and point-in-time recovery. Which option should be used?

A. File Gateway
B. Volume Gateway with cached volumes
C. Volume Gateway with stored volumes
D. Tape Gateway

Correct answer: C. Volume Gateway with stored volumes

Explanation: Stored volumes keep the complete data set on premises and asynchronously back it up to S3, with point-in-time EBS snapshots. Cached volumes keep the authoritative data set in S3, which does not meet the requirement that the complete data set remain local.

Question 3

An organization uses a supported enterprise backup application and wants to eliminate physical tape handling without redesigning its existing tape-based backup process. Archived backups should use the lowest-cost long-term AWS storage. Which solution is most appropriate?

A. File Gateway with SMB
B. Volume Gateway with cached volumes
C. Tape Gateway with S3 Glacier Deep Archive
D. Amazon S3 Standard accessed directly by the backup application

Correct answer: C. Tape Gateway with S3 Glacier Deep Archive

Explanation: Tape Gateway presents virtual tapes and integrates with compatible backup software. Active virtual tapes are stored in S3, and ejected tapes can be archived in S3 Glacier or S3 Glacier Deep Archive.

Question 4

A team incorrectly proposes File Gateway because it believes the application needs “storage in S3.” Testing shows the application requires a raw block device and communicates through iSCSI. What should the architect recommend?

A. File Gateway because S3 is the backend
B. Volume Gateway because it provides iSCSI block volumes
C. Tape Gateway because it supports large objects
D. NFS mounted directly from Amazon S3

Correct answer: B. Volume Gateway because it provides iSCSI block volumes

Explanation: The client-side protocol is the key decision point. File Gateway provides NFS or SMB, while Volume Gateway provides iSCSI block storage.

Question 5

A company wants AWS to store the complete data set for an on-premises workload, while only the active working set is retained locally to reduce latency. Which Storage Gateway configuration meets this requirement?

A. File Gateway with no cache
B. Volume Gateway with cached volumes
C. Volume Gateway with stored volumes
D. Tape Gateway with all tapes retained locally

Correct answer: B. Volume Gateway with cached volumes

Explanation: Cached volume mode stores the complete data set in S3 and maintains a local cache of frequently accessed data. Stored volume mode has the opposite primary placement: the complete data set remains on premises.