When studying for the AWS Certified Cloud Practitioner (CLF-C02) exam, understanding file systems in AWS, including cached file systems, is fundamental. One of the most common AWS tools in this category is AWS Storage Gateway, a hybrid storage service that enables on-premises applications to seamlessly use AWS Cloud storage.
The AWS Storage Gateway supports a cached volume mode which allows users to store primary data in Amazon S3, while retaining frequently accessed data in on-premises storage. The integration between your local storage environment and the AWS Cloud Storage ensures low-latency access to frequently accessed data (hot data), which is cached on-site, with durable, secure, and scalable off-site storage for all the data.
Understanding AWS Storage Gateway
AWS Storage Gateway is instrumental in smoothing the transition between local storage resources and AWS Cloud storage. It offers file, tape, and volume gateway configurations to cater to various organizational needs. When working with cached file systems, the volume gateway configuration is typically utilized.
The Volume Gateway presents your applications with disk volumes using the iSCSI block protocol. Data written to these volumes is maintained on your on-premise storage hardware while being asynchronously transferred to AWS, where it is stored in Amazon S3 as Amazon EBS snapshots. Volume Gateways are available in two modes: stored and cached.
Comparing Stored and Cached Volumes
| Stored Volumes | Cached Volumes |
|---|---|
| Entire dataset is stored on-site and is asynchronously backed up to AWS S3. | Only the frequently accessed data is retained on-site, and the complete dataset is stored in the AWS S3. |
| Ideal for low-latency access to the entire dataset. | Ideal when regular data access is required, but the complete dataset doesn’t need to be locally present. |
| You can store up to 16 TB data on each volume and up to 512 volumes. | You can store up to 32 TB data on each volume and up to 1500 volumes. |
Working with Cached Volumes in AWS Storage Gateway
The use of cached volumes allows you to leverage Amazon S3’s scalability and data protection features, while providing an on-premise cache to your most used data.
To create a cached volume, you would go through the following steps:
- Navigate to the AWS Management Console and open the AWS Storage Gateway service.
- Click on “Create gateway”, then choose “Volume gateway” as the gateway type and specify “Cached volumes”.
- Configure the gateway details – Amazon EC2 instance type, VPC settings, security group, and the IP address of the on-premises gateway.
Remember, understanding concepts like cached file systems and tools like the AWS Storage Gateway is essential for the AWS Certified Cloud Practitioner (CLF-C02) exam. Depending on your application’s requirements, knowing when to use cached volumes instead of stored volumes can help you make the most out of AWS services while optimizing your operational costs.
Moreover, mastering AWS Storage Gateway and its functionality provides you with key answers to questions about hybrid cloud implementations as well as the practical skills needed to implement real-world solutions.
Practice Test
True/False: AWS Storage Gateway does not support multiple types of cached file systems.
- True
- False
Answer: False
Explanation: AWS Storage Gateway supports cached volumes that give your on-premises applications low-latency access to virtually unlimited compute and storage in the AWS Cloud.
Which of the following are cached file systems supported by AWS?
- a) File Gateway
- b) Volume Gateway
- c) Tape Gateway
- d) Magnetic Gateway
Answer: a) File Gateway, b) Volume Gateway, c) Tape Gateway
Explanation: AWS Storage Gateway supports three types of gateways: File Gateway for flat files, Tape Gateway for back up, and Volume Gateway which provides cached access to your data.
True/False: You cannot use AWS Storage Gateway in a hybrid environment.
- True
- False
Answer: False
Explanation: AWS Storage Gateway integrates on-premises IT environments with cloud storage for backup and restore, disaster recovery, and tiered storage.
How can you access your cached volumes in AWS Storage Gateway?
- a) iSCSI
- b) NFS
- c) CIFS
- d) AFP
Answer: a) iSCSI
Explanation: Cached volumes make it easy to use Amazon S3 for storage accessed via iSCSI devices.
Multiple select: What are the benefits of using AWS Storage Gateway?
- a) Low-latency access
- b) Data Recovery
- c) Increased cost
- d) Scalability
Answer: a) Low-latency access, b) Data Recovery, d) Scalability
Explanation: AWS Storage Gateway provides low-latency performance by maintaining frequently accessed data on-premises while securely storing all of your data encrypted in AWS.
True/False: Volume Gateway can’t be used to incrementally backup on-premises data to AWS.
- True
- False
Answer: False
Explanation: Volume Gateway provides cached volumes that let you use AWS for incrementally backing up on-premises data to Amazon S3 for durable off-site recovery.
In AWS Storage Gateway, your data is transferred over what kind of connection?
- a) Open Internet Connection
- b) HTTP
- c) IPsec VPN
- d) A Direct connect Line
Answer: c) IPsec VPN
Explanation: AWS Storage Gateway transfers data to and from AWS over an IPsec VPN for increased security.
True/False: In AWS Storage Gateway, all data stored in your file shares and volume gateways are automatically encrypted.
- True
- False
Answer: True
Explanation: All data transferred between your gateway and AWS storage is encrypted and all data stored in your file shares and volume gateways are also encrypted.
What is the basic unit of deployment for AWS file gateway?
- a) Volume
- b) File share
- c) Bucket
- d) Folder
Answer: b) File share
Explanation: File share is the basic unit of deployment for a file gateway, and each file gateway can support up to 10 file shares.
True/False: Cached volumes cannot store data in Amazon S3 and retain frequently accessed data on your on-premises storage hardware.
- True
- False
Answer: False
Explanation: Cached volumes, part of AWS storage gateway, can store data in Amazon S3 and retain frequently accessed data on your on-premises storage hardware. They provide your applications with low-latency access to their frequently accessed data.
Interview Questions
What is AWS Storage Gateway?
AWS Storage Gateway is a hybrid cloud storage service that gives you on-premises access to virtually unlimited cloud storage. It provides low-latency access to data through transparent local caching.
How does AWS Storage Gateway cache data?
AWS Storage Gateway maintains a cache of frequently accessed data subsets locally, while storing all data securely and durably in Amazon S3 or Amazon Glacier.
What are the three types of AWS Storage Gateway?
The three types of AWS Storage Gateway are File Gateway, Volume Gateway, and Tape Gateway.
What is the role of File Gateway in the AWS Storage Gateway service?
File Gateways provide a virtual on-premises file server, which enables you to store and retrieve files as objects in Amazon S3.
Can we directly interact with the cached volumes in AWS storage gateway?
Yes, applications can interact with the cached volumes using the iSCSI block protocol.
What is the purpose of volume gateways in AWS Storage Gateway?
Volume Gateways provide cloud-backed storage volumes that you can mount as Internet Small Computer System Interface (iSCSI) devices from your on-premises application servers.
How can you access data stored in AWS cloud through AWS Storage Gateway?
AWS Storage Gateway provides a standard set of storage protocols such as iSCSI, SMB, and NFS for access to data stored in the AWS cloud.
How do Storage Gateway’s cached volumes work?
Cached volumes store your primary data in S3 while retaining your frequently accessed data locally in a cache for low-latency access.
Can AWS Storage Gateway be used for disaster recovery?
Yes, AWS Storage Gateway can be used for disaster recovery, data mirroring, and providing on-premises applications access to data in the cloud.
Which types of data transfers are free of charge in AWS Storage Gateway?
Data transfer from AWS Storage Gateway to Amazon S3, Amazon Glacier, Amazon EBS, and AWS Direct Connect (if used) within the same AWS Region is free of charge.
What data is backed up during AWS Storage Gateway’s scheduled backup of cached volume?
Only the data that has been changed since the last backup is stored in the cloud, minimizing the amount of data transferred over the network.
What happens when new data is written to a cached volume?
When new data is written to a cached volume, the data is stored in the cache, and uploaded to Amazon S3 in the background.
How can a user ensure that data written to the file gateway is secure?
For data written to the file gateway, AWS Storage Gateway stores data encrypted at rest in S3 and transfers data securely over SSL.
Can AWS Storage Gateway be set up in places with low bandwidth, high latency connectivity?
Yes, AWS Storage Gateway can be set up in places with low bandwidth, high latency connectivity to minimize data transfer while maintaining fast local access to your most used data.
Is it possible to control access to objects in S3 that have been written through AWS File Gateway?
Yes, it is possible to use S3 bucket policies to control access to objects written through AWS File Gateway.
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