Study guide
Technical reference and lesson notes
AWS Storage Gateway: File, Volume, and Tape Gateway Decision Guide
Purpose of This Lesson
AWS Storage Gateway connects on-premises storage environments with AWS storage services. For the SOA-C03 exam, the most important skill is recognizing which gateway type and access protocol match a workload’s requirements:
- File Gateway for file-based access through NFS or SMB while storing data as S3 objects.
- Volume Gateway for block-based storage through iSCSI, with either cached or stored volume operation.
- Tape Gateway for virtual tape libraries used by backup applications.
The gateways can be deployed as virtual appliances on VMware, Hyper-V, or KVM, or as a hardware appliance.
Key Concepts
Gateway Deployment and Data Flow
A Storage Gateway appliance runs in the on-premises environment and provides a familiar storage interface to local servers or backup applications. Data is transferred to AWS over an encrypted connection. Depending on the gateway type, the AWS-side destination can include:
- Amazon S3 for file gateway objects, volume gateway data, and virtual tape data.
- Amazon EBS snapshots for volume gateway stored volumes.
- S3 Glacier or S3 Glacier Deep Archive for virtual tapes after they are ejected from the virtual tape library.
Local caching is used by file gateways and cached volume gateways to provide lower-latency access to recently or frequently used data.
File Gateway
File Gateway presents a file system interface to clients while storing files as objects in Amazon S3. Client servers mount shares using:
- NFS
- SMB
A local cache keeps recently accessed data available with lower latency. This allows an application that expects a traditional file system to use S3 as its underlying cloud storage. File Gateway is therefore useful when the application requires file protocols but the organization wants the cost and durability characteristics of object storage.
Volume Gateway
Volume Gateway provides block storage through iSCSI. It has two operating modes:
#### Cached Volume Mode
- The complete data set is stored in Amazon S3.
- Frequently or recently accessed data is cached on premises.
- Local applications access the volumes through iSCSI.
Choose cached volume mode when the primary copy should be in AWS while the on-premises cache provides local access to active data.
#### Stored Volume Mode
- The complete data set is kept on premises.
- Data is asynchronously backed up to Amazon S3.
- Point-in-time snapshots of the volumes are created as EBS snapshots.
Choose stored volume mode when the on-premises environment must retain the full working data set locally and AWS is used for backup and point-in-time recovery support.
Tape Gateway
Tape Gateway provides a virtual tape library for backup applications. Backup servers connect to virtual media changers and tape drives exposed by the gateway. The backup data is written to S3, and virtual tapes can later be archived to S3 Glacier or S3 Glacier Deep Archive after being ejected.
The lecture identifies support for common backup applications such as NetBackup, Backup Exec, and Veeam. Virtual tape configuration includes selecting tape sizes. The gateway can support up to 1,500 virtual tapes with a maximum capacity of 1 petabyte.
Data is transferred using SSL encryption and is encrypted on the server side using SSE-S3.
Exam- or Assessment-Relevant Takeaways
- A requirement for NFS or SMB file shares backed by S3 points to File Gateway.
- A requirement for block storage points to Volume Gateway, because it uses iSCSI.
- Cached volume mode places the full data set in S3 and keeps active data locally cached.
- Stored volume mode keeps the complete data set on premises and asynchronously backs it up to S3, with point-in-time EBS snapshots.
- A requirement to modernize or extend an existing tape-based backup workflow points to Tape Gateway.
- File Gateway and Volume Gateway are the primary areas emphasized in the lecture; do not confuse file protocols, block protocols, and object storage.
- The gateway is deployed on premises or as a hardware appliance; it is not simply a native S3 client mounted directly by an application.
Tool / Feature Decision Guide
| Requirement or workload | Select | Decisive reason |
|---|---|---|
| Existing application needs NFS or SMB shares | File Gateway | Provides file-based access while storing files as S3 objects |
| Application needs block devices over iSCSI | Volume Gateway | Provides block-based volumes |
| Full data set should reside in AWS, with active data cached locally | Volume Gateway — Cached Volume Mode | S3 stores the full data set; local cache serves active data |
| Full data set must remain on premises, with AWS backup | Volume Gateway — Stored Volume Mode | Local storage holds the complete data set and S3 receives asynchronous backups |
| Existing backup software uses virtual or physical tape workflows | Tape Gateway | Presents a virtual tape library with virtual media changers and tape drives |
| Backup tapes need longer-term archival | Tape Gateway with Glacier or Glacier Deep Archive | Ejected virtual tapes can be moved to archival storage classes |
Common Traps / Misconceptions
- File Gateway is not block storage. It uses NFS or SMB and stores files as S3 objects.
- Volume Gateway is not a file share. It exposes block-based volumes through iSCSI.
- Cached volume mode and stored volume mode are not interchangeable. Cached mode keeps the primary full data set in S3; stored mode keeps the full data set on premises.
- File Gateway caching does not change S3 into a block device. The local cache improves access to recently used file data, but the backend remains S3 object storage.
- Tape Gateway is not the same as a general-purpose file gateway. It is designed around backup applications, virtual tapes, media changers, and tape drives.
- Tape data does not necessarily remain in S3 Standard forever. Ejected virtual tapes can be stored in Glacier or Glacier Deep Archive.
- Encryption details matter. The lecture specifies SSL for transfer and SSE-S3 for server-side encryption.
- Do not select a gateway based only on the desired AWS storage class. First identify the client protocol and workload type.
Real-World Engineer / Analyst Notes
- Start troubleshooting by identifying what the client believes it is connecting to: an NFS/SMB share, an iSCSI block volume, or a tape library.
- Confirm whether the workload requires the entire data set locally or only a working set. That distinction separates stored volume mode from cached volume mode.
- Local cache sizing and workload access patterns affect the practical experience of file and cached volume gateways, even though the gateway’s cloud data destination remains S3.
- For backup migrations, verify that the existing backup application supports the virtual tape workflow and that the planned archive storage class matches retention requirements.
- Treat protocol compatibility as a first-order design constraint. An application written for file access cannot use an iSCSI volume merely because both solutions ultimately use AWS storage.
Quick Reference Summary
- File Gateway: NFS/SMB file access, local cache, files stored as S3 objects.
- Volume Gateway: iSCSI block storage.
- Cached volumes: full data set in S3, active data cached locally.
- Stored volumes: full data set on premises, asynchronous S3 backup, point-in-time EBS snapshots.
- Tape Gateway: virtual tape library for backup software; data goes to S3 and ejected tapes can move to Glacier or Glacier Deep Archive.
- Deployment: VMware, Hyper-V, KVM, or hardware appliance.
- Security: SSL encryption in transit and SSE-S3 server-side encryption as described in the lecture.
Flashcards
Q: An on-premises application requires an SMB share, but the organization wants the files stored in Amazon S3. Which Storage Gateway type fits?
A: Use File Gateway. It provides SMB or NFS access while storing the files as S3 objects.
Q: When should Volume Gateway be selected instead of File Gateway?
A: Select Volume Gateway when the application requires block-based storage through iSCSI rather than a file share through NFS or SMB.
Q: What is the decisive storage-location difference between cached volume mode and stored volume mode?
A: Cached volume mode keeps the complete data set in S3 and caches active data locally. Stored volume mode keeps the complete data set on premises and backs it up asynchronously to S3.
Q: A workload needs low-latency access to frequently used data, but its complete data set should be maintained in AWS. Which volume mode is appropriate?
A: Use cached volume mode, because the full data set resides in S3 while frequently accessed data is cached on premises.
Q: A workload must retain its entire working data set locally while sending backups to AWS. Which mode should be chosen?
A: Use stored volume mode. The full data set remains on premises, and backups are sent asynchronously to S3.
Q: Which protocol does Volume Gateway use for block-based access?
A: Volume Gateway uses iSCSI. It does not provide NFS or SMB file shares.
Q: What protocol choices does File Gateway provide to on-premises servers?
A: File Gateway provides NFS and SMB access to files that are stored as objects in S3.
Q: A company wants to replace physical tape handling without changing its established backup software workflow. Which gateway should it evaluate?
A: Evaluate Tape Gateway, which provides a virtual tape library with virtual media changers and tape drives for supported backup applications.
Q: When can Tape Gateway data be placed in Glacier or Glacier Deep Archive?
A: Virtual tapes can be moved to Glacier or Glacier Deep Archive after they are ejected from the virtual tape library.
Q: Which AWS destinations are associated with Volume Gateway stored volumes in the lecture?
A: The data is backed up to S3, and point-in-time snapshots of the volumes are created as EBS snapshots.
Q: What is the main architectural benefit of File Gateway?
A: It lets file-based applications use familiar NFS or SMB interfaces while taking advantage of S3 object storage on the backend.
Q: Where can a Storage Gateway appliance be deployed?
A: It can run as a virtual appliance on VMware, Hyper-V, or KVM, or it can be deployed as a hardware appliance.
Q: What encryption mechanisms are identified for Storage Gateway data?
A: Data is transferred using SSL encryption and is encrypted on the server side using SSE-S3.
Practice Questions
Question 1
An application can only mount an NFS share. The operations team wants the underlying data stored in Amazon S3 and needs local caching for recently accessed files. Which solution should they choose?
A. Cached Volume Gateway
B. Stored Volume Gateway
C. File Gateway
D. Tape Gateway
Correct answer: C. File Gateway. The decisive clues are the NFS file interface, S3 object storage, and file-oriented local cache.
Question 2
A database workload requires block-based volumes over iSCSI. The complete data set should be stored in S3, but the most frequently accessed data must be available through an on-premises cache. Which configuration fits?
A. File Gateway
B. Volume Gateway in cached volume mode
C. Volume Gateway in stored volume mode
D. Tape Gateway
Correct answer: B. Volume Gateway in cached volume mode. iSCSI identifies Volume Gateway, and storing the full data set in S3 with a local active-data cache identifies cached mode.
Question 3
An organization must keep its full data set on premises for local operation but wants asynchronous AWS backups and point-in-time volume snapshots. Which choice is appropriate?
A. File Gateway
B. Volume Gateway in cached volume mode
C. Volume Gateway in stored volume mode
D. Tape Gateway archived to Glacier
Correct answer: C. Volume Gateway in stored volume mode. Stored mode retains the entire data set locally, backs it up asynchronously to S3, and creates point-in-time EBS snapshots.
Question 4
A backup team uses Veeam and wants a virtual tape library. After tapes are ejected, they should be retained in a lower-cost archival storage class. Which gateway and workflow should be selected?
A. File Gateway with SMB and S3 Standard
B. Cached Volume Gateway with iSCSI and EBS snapshots
C. Stored Volume Gateway with NFS and Glacier
D. Tape Gateway with S3 followed by Glacier or Glacier Deep Archive
Correct answer: D. Tape Gateway with S3 followed by Glacier or Glacier Deep Archive. The virtual tape library and backup application identify Tape Gateway, while ejected tapes can be archived in the specified classes.
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Study AWS Storage Gateway architectures, gateway types, protocols, storage destinations, operating modes, and selection tradeoffs for the SOA-C03 CloudOps Engineer Associate exam.
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AWS Storage Gateway, AWS Certified CloudOps Engineer, SOA-C03, File Gateway, Volume Gateway, Tape Gateway, Amazon S3, iSCSI, NFS, SMB, AWS Backup Storage