--- tags: - cloud - l1 - flashcard-deck - aws-storage --- [Portal](../../../../library/portal/index.md) | **Level:** [L1: Foundations](../../../../library/portal/levels.md) | **Topics:** [AWS S3 Deep Dive](../../../../library/portal/topics.md) | **Domain:** Cloud id category difficulty tags question answer source_path aws-storage/02ad435dcca6 aws-storage easy aws, s3 Explain what is AWS S3? - S3 is a object storage service which is fast, scalable and durable. S3 enables customers to upload, download or store any file or object that is up to 5 TB in size. \n- S3 stands for: Simple Storage Service\n- As a user you don't have to worry about filesystems or disk space\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/140-explain-what-is-aws-s3.txt aws-storage/0756e962f6c6 aws-storage medium aws, efs True or False? EFS requires the user to perform capacity planning as it doesn't scales automatically False. EFS scales automatically and you pay-per-use.\n\nRemember: EFS = Elastic File System. NFS-compatible, shared across multiple EC2 instances. Auto-scales, pay per GB stored. Think 'shared network drive.' projects/knowledge/interview/aws/051-true-or-false-efs-requires-the-user-to-perform-cap.txt aws-storage/092b10681c38 aws-storage medium aws, ami, s3 Explain AWS pricing model "It mainly works on ""pay-as-you-go"" meaning you pay only for what are using and when you are using it.\nIn s3 you pay for 1. How much data you are storing 2. Making requests (PUT, POST, ...)\nIn EC2 it's based on the purchasing option (on-demand, spot, ...), instance type, AMI type and the region used.\n\nMore on AWS pricing model [here](https://aws.amazon.com/pricing)\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts." projects/knowledge/interview/aws/347-explain-aws-pricing-model.txt aws-storage/0a50b5038904 aws-storage easy aws, s3 What is AWS Guarduty? "AWS definition: ""Amazon GuardDuty is a threat detection service that continuously monitors for malicious activity and unauthorized behavior to protect your Amazon Web Services accounts, workloads, and data stored in Amazon S3"" \nMonitor VPC Flow lows, DNS logs, CloudTrail S3 events and CloudTrail Mgmt events.\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts." projects/knowledge/interview/aws/220-what-is-aws-guarduty.txt aws-storage/0cc0306af16f aws-storage hard aws, encryption, s3 Why would someone choose to use SSE-KMS instead of SSE-S3? SSE-KMS provides control over who has access to the keys and you can also enabled audit trail.\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/155-why-would-someone-choose-to-use-sse-kms-instead-of.txt aws-storage/0d8e0343f759 aws-storage hard aws, ami, ebs, ec2 What are some limitations of EC2 hibernate option? * Instance RAM size is limited\n* Root volume must be encrypted EBS\n* Hibernation time is limited\n* Doesn't supports all instances types\n* No support for bare metal. Only On-Demand and Reserved instances\n* Doesn't supports all AMIs\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/086-what-are-some-limitations-of-ec2-hibernate-option.txt aws-storage/0f8fb83e7d7c aws-storage hard aws, encryption True or False? In case of SSE-C HTTPS must be used and encryption key must be provided in headers for every HTTP request True. With SSE-C (Server-Side Encryption with Customer-Provided Keys), you must use HTTPS and include the encryption key in the request headers for every S3 operation.\n\nRemember: S3 encryption: SSE-S3 (AWS-managed keys), SSE-KMS (customer-managed via KMS), SSE-C (customer-provided keys). Default encryption is now SSE-S3. projects/knowledge/interview/aws/157-true-or-false-in-case-of-sse-c-https-must-be-used-.txt aws-storage/1379df643919 aws-storage medium aws, ebs If you need an EBS volume for infrequently data access, which volume type would you use? Cold HDD (sc1). It's the lowest-cost EBS volume for infrequent access — throughput-optimized at 250 MB/s max, ideal for archival or sequential cold data.\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/042-if-you-need-an-ebs-volume-for-infrequently-data-ac.txt aws-storage/14833f122f01 aws-storage medium aws, storage-gateway Explain the following Storage Gateway deployments types Explained in detail [here](https://aws.amazon.com/storagegateway/faqs)\n\nRemember: S3 storage classes from hot to cold: Standard > Intelligent-Tiering > Standard-IA > One Zone-IA > Glacier Instant > Glacier Flexible > Deep Archive.\n\nGotcha: S3 charges for storage, requests, and data transfer out. Data transfer IN is free. Optimize costs with lifecycle policies and the right storage class. projects/knowledge/interview/aws/165-explain-the-following-storage-gateway-deployments-.txt aws-storage/16570a8b3e31 aws-storage medium aws, glacier, s3 What Glacier retrieval options are available for the user? Expedited, Standard and Bulk\n\nRemember: S3 tiers by cost (high to low): Standard > Intelligent-Tiering > IA > One Zone-IA > Glacier Instant > Glacier Flexible > Glacier Deep Archive. Access speed decreases as cost decreases. projects/knowledge/interview/aws/162-what-glacier-retrieval-options-are-available-for-t.txt aws-storage/1b5bde7648da aws-storage medium aws, ebs What are the use cases for using EBS snapshots? * Backups of the data\n* Moving the data between AZs\n\nRemember: EBS = Elastic Block Store. Network-attached block storage for EC2. Think 'virtual hard drive.' Types: gp3 (general), io2 (high IOPS), st1 (throughput), sc1 (cold). projects/knowledge/interview/aws/036-what-are-the-use-cases-for-using-ebs-snapshots.txt aws-storage/1f324f6cb069 aws-storage medium aws, s3 Explain the concept of AWS Lambda Triggers. Lambda Triggers: They're events that invoke Lambda functions automatically when a particular event occurs in other AWS services. For instance, S3 upload triggers a Lambda function.\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/439-explain-the-concept-of-aws-lambda-triggers.txt aws-storage/22debe40d2d4 aws-storage medium aws, storage-gateway You would like to have on-perm storage access to AWS storage. What would you use for that? Storage Gateway\n\nRemember: S3 storage classes from hot to cold: Standard > Intelligent-Tiering > Standard-IA > One Zone-IA > Glacier Instant > Glacier Flexible > Deep Archive.\n\nGotcha: S3 charges for storage, requests, and data transfer out. Data transfer IN is free. Optimize costs with lifecycle policies and the right storage class. projects/knowledge/interview/aws/300-you-would-like-to-have-on-perm-storage-access-to-a.txt aws-storage/24dbff4f61c8 aws-storage medium aws, efs What are some use cases for using EFS? * Data sharing (e.g. developers working on the same source control)\n* Web serving\n* Content management\n\nRemember: EFS = Elastic File System. NFS-compatible, shared across multiple EC2 instances. Auto-scales, pay per GB stored. Think 'shared network drive.' projects/knowledge/interview/aws/050-what-are-some-use-cases-for-using-efs.txt aws-storage/283a870a1f5a aws-storage medium aws, ebs Explain EBS Snapshots EBS snapshots used for making a backup of the EBS volume at point of time.\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/035-explain-ebs-snapshots.txt aws-storage/286ca6a0e3b8 aws-storage easy aws, s3, transfer "What is ""Amazon S3 Transfer Acceleration""?" "AWS definition: ""Amazon S3 Transfer Acceleration enables fast, easy, and secure transfers of files over long distances between your client and an S3 bucket""\n\nLearn more [here](https://docs.aws.amazon.com/AmazonS3/latest/dev/transfer-acceleration.html)\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB." projects/knowledge/interview/aws/167-what-is-amazon-s3-transfer-acceleration.txt aws-storage/2b5de0dbcdc2 aws-storage medium aws, efs What EFS storage tiers are there? * Standard: frequently accessed files\n* Infrequent access: lower prices to store files but it also costs to retrieve them\n\nRemember: EFS = Elastic File System. NFS-compatible, shared across multiple EC2 instances. Auto-scales, pay per GB stored. Think 'shared network drive.' projects/knowledge/interview/aws/055-what-efs-storage-tiers-are-there.txt aws-storage/2f60079fdf16 aws-storage medium aws, s3 True or False? Buckets are defined globally False. They are defined at the region level.\n\nRemember: S3 storage classes from hot to cold: Standard > Intelligent-Tiering > Standard-IA > One Zone-IA > Glacier Instant > Glacier Flexible > Deep Archive.\n\nGotcha: S3 charges for storage, requests, and data transfer out. Data transfer IN is free. Optimize costs with lifecycle policies and the right storage class. projects/knowledge/interview/aws/142-true-or-false-buckets-are-defined-globally.txt aws-storage/312e87b368a6 aws-storage easy aws, storage-gateway What is the difference between stored volumes and cached volumes? Stored Volumes - Data is located at customer's data center and periodically backed up to AWS\nCached Volumes - Data is stored in AWS cloud and cached at customer's data center for quick access\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/166-what-is-the-difference-between-stored-volumes-and-.txt aws-storage/33f571cdbda3 aws-storage hard aws, s3 What would you use for running SQL queries interactively on S3? Amazon Athena. It runs standard SQL queries directly against data in S3 (CSV, JSON, Parquet, ORC) using a serverless Presto engine — no infrastructure to manage, pay per query.\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/282-what-would-you-use-for-running-sql-queries-interac.txt aws-storage/343edf3d6400 aws-storage hard aws, ebs What if I have lost the Pem file for ubuntu user of an ec2-instance ? It's advisable to create a new key pair and associate it with the instance. Otherwise, if an EBS-backed instance, stopping it, detaching the root volume, attaching it to another instance, modifying the authorized_keys file, then reattaching it to the original instance might help recover access.\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/453-what-if-i-have-lost-the-pem-file-for-ubuntu-user-o.txt aws-storage/3772b5339aeb aws-storage hard aws, ebs You try to use an detached EBS volume from us-east-1b in us-east-1a, but it fails. What might be the reason? EBS volumes are locked to a specific availability zone. To use them in another availability zone, you need to take a snapshot and restore it in the destination availability zone.\n\nRemember: EBS = Elastic Block Store. Network-attached block storage for EC2. Think 'virtual hard drive.' Types: gp3 (general), io2 (high IOPS), st1 (throughput), sc1 (cold). projects/knowledge/interview/aws/384-you-try-to-use-an-detached-ebs-volume-from-us-east.txt aws-storage/37fd292917b3 aws-storage hard aws, ami, ebs, s3 Can you host dynamic websites on S3? What about static websites? No. S3 support only statis hosts. On a static website, individual webpages include static content. They might also contain client-side scripts. By contrast, a dynamic website relies on server-side processing, including server-side scripts such as PHP, JSP, or ASP.NET. Amazon S3 does not support server-side scripting.\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/169-can-you-host-dynamic-websites-on-s3-what-about-sta.txt aws-storage/38c058256d7b aws-storage medium aws, ebs If you need an EBS volume for workloads that require good performance but the cost is also an important aspect for you, which volume type would you use? General Purpose SSD (gp2 or gp3). These volumes balance price and performance, delivering up to 16,000 IOPS and 1,000 MB/s throughput (gp3), suitable for boot volumes, dev/test, and most production workloads.\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/040-if-you-need-an-ebs-volume-for-workloads-that-requi.txt aws-storage/3df8eb6a35e4 aws-storage hard aws, ami, s3 How to rename a bucket in S3? A S3 bucket name is immutable. That means it's not possible to change it, without removing and creating a new bucket.\n\nThis is why the process for renaming a bucket is as follows:\n\n* Create a new bucket with the desired name\n* Move the data from the old bucket to it\n* Delete the old bucket\n\nWith the AWS CLI that would be:\n\n```sh\n# Create new bucket\naws s3 mb s3://[NEW_BUCKET_NAME]\n# Sync the content from the old bucket to the new bucket\n$ aws s3 sync s3://[OLD_BUCKET_NAME] s3://[NEW_BUCKET_NAME]\n# Remove old bucket\n$ aws s3 rb --force s3://[OLD_BUCKET_NAME]\n``` projects/knowledge/interview/aws/143-how-to-rename-a-bucket-in-s3.txt aws-storage/4103b7972623 aws-storage easy aws, efs What is the default EFS mode? Performance Mode (General Purpose): Used for web serving, CMS, ... anything that is sensitive to latency.\n\nRemember: EFS = Elastic File System. NFS-compatible, shared across multiple EC2 instances. Auto-scales, pay per GB stored. Think 'shared network drive.' projects/knowledge/interview/aws/054-what-is-the-default-efs-mode.txt aws-storage/41f13ea5a2b2 aws-storage medium aws, ebs If you need an EBS volume for low latency workloads, which volume type would you use? Provisioned IOPS SSD (io1 or io2). These volumes are designed for I/O-intensive workloads requiring sustained, low-latency performance — up to 64,000 IOPS and 1,000 MB/s — such as large relational databases and latency-sensitive applications.\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/039-if-you-need-an-ebs-volume-for-low-latency-workload.txt aws-storage/44d9c305db5f aws-storage hard aws, encryption, s3 Describe shortly how SSE-C encryption works 1. User uploads a file to S3 using HTTPS while providing data key in the header\n2. AWS S3 performs the encryption using the provided data key and encrypted object is stored in the bucket\n\nIf a user would like to get the object, the same data key would have to be provided.\n\nRemember: S3 encryption: SSE-S3 (AWS-managed keys), SSE-KMS (customer-managed via KMS), SSE-C (customer-provided keys). Default encryption is now SSE-S3. projects/knowledge/interview/aws/158-describe-shortly-how-sse-c-encryption-works.txt aws-storage/4e64a60341ae aws-storage medium aws, s3, transfer What would you use to transfer files over long distances between a client and an S3 bucket? Amazon S3 Transfer Acceleration\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/296-what-would-you-use-to-transfer-files-over-long-dis.txt aws-storage/53e216836aac aws-storage medium aws, encryption, s3 What encryption types supported by S3? * SSE-S3\n* SSE-KMS\n* SSE-C\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/151-what-encryption-types-supported-by-s3.txt aws-storage/59245c1e356c aws-storage easy aws, glacier, lifecycle, s3 What is a storage class? What storage classes are there? Each object has a storage class assigned to, affecting its availability and durability. This also has effect on costs.\nStorage classes offered today:\n * Standard:\n * Used for general, all-purpose storage (mostly storage that needs to be accessed frequently)\n * The most expensive storage class\n * 11x9% durability\n * 2x9% availability\n * Default storage class\n\nRemember: S3 tiers by cost (high to low): Standard > Intelligent-Tiering > IA > One Zone-IA > Glacier Instant > Glacier Flexible > Glacier Deep Archive. Access speed decreases as cost decreases. projects/knowledge/interview/aws/160-what-is-a-storage-class-what-storage-classes-are-t.txt aws-storage/595ea89c5d3d aws-storage hard aws, encryption, s3 True or False? In case of SSE-C encryption, both S3 and you manage the keys False. You manage the keys. It's customer provided keys.\n\nRemember: S3 encryption: SSE-S3 (AWS-managed keys), SSE-KMS (customer-managed via KMS), SSE-C (customer-provided keys). Default encryption is now SSE-S3. projects/knowledge/interview/aws/156-true-or-false-in-case-of-sse-c-encryption-both-s3-.txt aws-storage/5a624284bfd6 aws-storage medium aws, ebs, ec2 Which EBS volume types can be used as boot volumes for EC2 instances? SSD: gp2, gp3, io1, io2\n\nRemember: S3 storage classes from hot to cold: Standard > Intelligent-Tiering > Standard-IA > One Zone-IA > Glacier Instant > Glacier Flexible > Deep Archive.\n\nGotcha: S3 charges for storage, requests, and data transfer out. Data transfer IN is free. Optimize costs with lifecycle policies and the right storage class. projects/knowledge/interview/aws/043-which-ebs-volume-types-can-be-used-as-boot-volumes.txt aws-storage/5b843778cfc1 aws-storage easy aws, transfer What is AWS Snowmobile? AWS Snowmobile is an Exabyte-scale data transfer service used to move extremely large amounts of data to AWS.\n\nLearn more [here](https://aws.amazon.com/snowmobile)\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/367-what-is-aws-snowmobile.txt aws-storage/6710c3543517 aws-storage hard aws, s3 A user is unable to access an s3 bucket. What might be the problem? There can be several reasons for that. One of them is lack of policy. To solve that, the admin has to attach the user with a policy what allows him to access the s3 bucket.\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/014-a-user-is-unable-to-access-an-s3-bucket-what-might.txt aws-storage/6ae54f3a6677 aws-storage hard aws, ebs What happens to EBS volumes when the instance is terminated? By default, the root volume is marked for deletion, while other volumes will still remain. \nYou can control what will happen to every volume upon termination.\n\nRemember: EBS = Elastic Block Store. Network-attached block storage for EC2. Think 'virtual hard drive.' Types: gp3 (general), io2 (high IOPS), st1 (throughput), sc1 (cold). projects/knowledge/interview/aws/033-what-happens-to-ebs-volumes-when-the-instance-is-t.txt aws-storage/6bfc2236c91e aws-storage hard aws, ebs, ec2, encryption How to encrypt an unencrypted EBS volume attached to an EC2 instance? "1. Create EBS snapshot of the volume\n2. Copy the snapshot and mark the ""Encrypt"" option\n3. Create a new EBS volume out of the encrypted snapshot\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise." projects/knowledge/interview/aws/388-how-to-encrypt-an-unencrypted-ebs-volume-attached-.txt aws-storage/6eda369e0167 aws-storage medium aws, s3 Explain Object Durability and Object Availability Object Durability: The percent over a one-year time period that a file will not be lost\nObject Availability: The percent over a one-year time period that a file will be accessible\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/147-explain-object-durability-and-object-availability.txt aws-storage/77be3f068c6d aws-storage medium aws, efs Which EFS mode would you use if you need to perform media processing? Performance Mode (Max I/O): It provides high throughput and scales to operations per second. Mainly used for big data, media processing, etc.\n\nRemember: EFS = Elastic File System. NFS-compatible, shared across multiple EC2 instances. Auto-scales, pay per GB stored. Think 'shared network drive.' projects/knowledge/interview/aws/053-which-efs-mode-would-you-use-if-you-need-to-perfor.txt aws-storage/79ef8140fb2b aws-storage easy aws, transfer What is AWS Snowball? A transport solution which was designed for transferring large amounts of data (petabyte-scale) into and out the AWS cloud.\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/174-what-is-aws-snowball.txt aws-storage/7ac25cac587b aws-storage medium aws, encryption, s3 Describe shortly how SSE-S3 (AES) encryption works 1. You upload a file to S3 using HTTP (or HTTPS) and header\n2. S3 uses the managed data key to encrypt it\n3. S3 stores the encrypted object in the bucket\n\nRemember: S3 encryption: SSE-S3 (AWS-managed keys), SSE-KMS (customer-managed via KMS), SSE-C (customer-provided keys). Default encryption is now SSE-S3. projects/knowledge/interview/aws/152-describe-shortly-how-sse-s3-aes-encryption-works.txt aws-storage/7d8e7f4959db aws-storage easy aws, ec2, efs What is Amazon EFS (Elastic File System) and when would you use it? "[AWS Docs](https://aws.amazon.com/efs): ""Amazon Elastic File System (Amazon EFS) provides a simple, scalable, fully managed elastic NFS file system for use with AWS Cloud services and on-premises resources.""\n\nIn simpler words, it's a network file system you can mount on one or more EC2 instances.\n\nRemember: EFS = Elastic File System. NFS-compatible, shared across multiple EC2 instances. Auto-scales, pay per GB stored. Think 'shared network drive.'" projects/knowledge/interview/aws/048-what-is-amazon-efs.txt aws-storage/871149b18c39 aws-storage medium aws, storage-gateway What is the AWS Storage Gateway and its use cases? Storage Gateway: It's a service connecting an on-premises software appliance with cloud-based storage to provide seamless integration. \nUse Cases: Backup, disaster recovery, and hybrid cloud storage are common scenarios. projects/knowledge/interview/aws/443-what-is-the-aws-storage-gateway-and-its-use-cases.txt\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. aws-storage/8da2eeb6df60 aws-storage medium aws, ebs, ec2 Explain EC2 hibernate "[AWS Docs](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Hibernate.html: ""Hibernation saves the contents from the instance memory (RAM) to your Amazon Elastic Block Store (Amazon EBS) root volume.""\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise." projects/knowledge/interview/aws/083-explain-ec2-hibernate.txt aws-storage/8e0713df82bc aws-storage medium aws, storage How many buckets can you create in AWS by default? 100 buckets per account.\n\nRemember: S3 storage classes from hot to cold: Standard > Intelligent-Tiering > Standard-IA > One Zone-IA > Glacier Instant > Glacier Flexible > Deep Archive.\n\nGotcha: S3 charges for storage, requests, and data transfer out. Data transfer IN is free. Optimize costs with lifecycle policies and the right storage class. projects/knowledge/interview/aws/467-s3-bucket-limit.txt aws-storage/8f369b358d8d aws-storage easy aws, s3 What is AWS Athena and when would you use it for querying data? Amazon Athena is an interactive query service that makes it easy to analyze data in Amazon S3 using standard SQL.\n\nLearn more about AWS Athena [here](https://aws.amazon.com/athena)\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/368-what-is-aws-athena.txt aws-storage/93e7f9e45ef6 aws-storage medium aws, ec2, efs What are the benefits of using AWS EFS (Elastic File System)? EFS: It's a file storage service providing scalable storage for use with Amazon EC2 instances. Benefits include high availability, durability, and compatibility with multiple EC2 instances.\n\nRemember: EFS = Elastic File System. NFS-compatible, shared across multiple EC2 instances. Auto-scales, pay per GB stored. Think 'shared network drive.' projects/knowledge/interview/aws/441-what-are-the-benefits-of-using-aws-efs-elastic-fil.txt aws-storage/9448d9ad214c aws-storage medium aws, ebs What EBS volume types are there? * HDD (st 1, sc 1): Low cost HDD volumes\n* SSD\n * io1, io2: Highest performance SSD\n * gp2, gp3: General purpose SSD\n\nRemember: EBS = Elastic Block Store. Network-attached block storage for EC2. Think 'virtual hard drive.' Types: gp3 (general), io2 (high IOPS), st1 (throughput), sc1 (cold). projects/knowledge/interview/aws/038-what-ebs-volume-types-are-there.txt aws-storage/954809d6c615 aws-storage medium aws, encryption, s3 True or False? In case of SSE-S3 (AES-256) encryption, you manage the key False. S3 manages the key and uses AES-256 algorithm for the encryption.\n\nRemember: S3 encryption: SSE-S3 (AWS-managed keys), SSE-KMS (customer-managed via KMS), SSE-C (customer-provided keys). Default encryption is now SSE-S3. projects/knowledge/interview/aws/153-true-or-false-in-case-of-sse-s3-aes-256-encryption.txt aws-storage/9d6259bbbb2c aws-storage medium aws, transfer Which service allows you to transfer large amounts (Petabytes) of data in and out of the AWS cloud? AWS Snowball — a physical edge computing and data transfer device that lets you move petabytes of data into or out of AWS. You load data onto the ruggedized appliance on-premises, ship it to AWS, and the data is imported into S3.\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/273-which-service-allows-you-to-transfer-large-amounts.txt aws-storage/9d81da1d251a aws-storage medium aws, s3 Explain data consistency S3 Data Consistency provides strong read-after-write consistency for PUT and DELETE requests of objects in the S3 bucket in all AWS Regions. S3 always return latest file version.\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/168-explain-data-consistency.txt aws-storage/9eead1fedf43 aws-storage easy aws, storage-gateway Explain what is Storage Gateway AWS Storage Gateway is a hybrid cloud storage service that gives you on-premises access to virtually unlimited cloud storage.\nMore on Storage Gateway [here](https://aws.amazon.com/storagegateway)\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/164-explain-what-is-storage-gateway.txt aws-storage/a2da34e1a503 aws-storage medium aws, glacier, lifecycle, s3 A customer would like to move data which is rarely accessed from standard storage class to the most cheapest class there is. Which storage class should be used? Glacier Deep Archive\n\nRemember: S3 tiers by cost (high to low): Standard > Intelligent-Tiering > IA > One Zone-IA > Glacier Instant > Glacier Flexible > Glacier Deep Archive. Access speed decreases as cost decreases. projects/knowledge/interview/aws/161-a-customer-would-like-to-move-data-which-is-rarely.txt aws-storage/a42f3748e465 aws-storage hard aws, s3 True or False? Every new S3 bucket is public by default False. A newly created bucket is private unless it was configured to be public.\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/148-true-or-false-every-new-s3-bucket-is-public-by-def.txt aws-storage/a7938fb03175 aws-storage hard aws, ebs, ec2 How to recover an ec2-instance if it crashes ? Depends on the type of instance and its stored data. For EBS-backed instances, the data persists on the EBS volume and can be attached to another instance. For instance store-backed instances, recovery would involve relaunching the instance, losing any non-persistent data.\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/458-how-to-recover-an-ec2-instance-if-it-crashes.txt aws-storage/ab44454413a9 aws-storage easy aws, storage What is Amazon S3 and what are its key storage features? An object storage service that stores data in buckets.\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/465-amazon-s3.txt aws-storage/aece5da3f6b5 aws-storage medium aws, ebs, ec2, encryption What's the difference between EBS and S3 in AWS? Amazon S3 (Simple Storage Service): It's object storage for files, images, videos, and backups with virtually unlimited storage capacity and internet accessibility.\nAmazon EBS (Elastic Block Store): It's block storage used for EC2 instances, behaving like a hard drive. It's more suitable for database storage and allows for snapshots and encryption.\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/422-whats-the-difference-between-ebs-and-s3-in-aws.txt aws-storage/b3c9f057dc21 aws-storage medium aws, ebs If you need an EBS volume for high-throughput, which volume type would you use? Provisioned IOPS SSD (io1 or io2). These volume types deliver the highest throughput and lowest latency of any EBS option — up to 64,000 IOPS and 1,000 MB/s — ideal for databases and analytics workloads requiring consistent I/O.\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/041-if-you-need-an-ebs-volume-for-high-throughput-whic.txt aws-storage/b3cd184ae067 aws-storage medium aws, s3 What are Roles in Kubernetes RBAC and how do they control access? "[AWS docs](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles.html): ""An IAM role is an IAM identity that you can create in your account that has specific permissions...it is an AWS identity with permission policies that determine what the identity can and cannot do in AWS.""\nFor example, you can make use of a role which allows EC2 service to access s3 buckets (read and write).\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts." projects/knowledge/interview/aws/012-what-are-roles.txt aws-storage/b4fb5350739a aws-storage medium aws, encryption Who or what manages the keys in the case of SSE-KMS encryption? The KMS service.\n\nRemember: S3 encryption: SSE-S3 (AWS-managed keys), SSE-KMS (customer-managed via KMS), SSE-C (customer-provided keys). Default encryption is now SSE-S3. projects/knowledge/interview/aws/154-who-or-what-manages-the-keys-in-the-case-of-sse-km.txt aws-storage/c1e52a657cf8 aws-storage hard aws, encryption, s3 What security measures have you taken in context of S3? * Don't make a bucket public.\n * Enable encryption if it's disabled.\n * Define an access policy\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/150-what-security-measures-have-you-taken-in-context-o.txt aws-storage/c3d535c274b4 aws-storage medium aws, ebs, efs, glacier Explain different types of volumes in AWS. In a cloud office, different types of volumes are like different storage spaces. EBS is like a hard drive, S3 is like a file cabinet, and Glacier is like a secure storage room for long-term archives. Some of them are EBS (Elastic Block Store), S3 (Object Storage), EFS (Elastic File System).\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/408-explain-different-types-of-volumes-in-aws.txt aws-storage/c6d874833083 aws-storage easy aws, storage "What is an ""EBS Snapshot""?" An incremental backup of an EBS volume stored in S3.\n\nRemember: EBS = Elastic Block Store. Network-attached block storage for EC2. Think 'virtual hard drive.' Types: gp3 (general), io2 (high IOPS), st1 (throughput), sc1 (cold). projects/knowledge/interview/aws/481-ebs-snapshot.txt aws-storage/c9c8a3e5758a aws-storage hard aws, ec2, efs You try to mount EFS on your EC2 instance and it doesn't work (hangs...) What might be a possible reason? Security group isn't attached to your EFS or it lacks a rule to allow NFS traffic.\n\nRemember: EFS = Elastic File System. NFS-compatible, shared across multiple EC2 instances. Auto-scales, pay per GB stored. Think 'shared network drive.' projects/knowledge/interview/aws/386-you-try-to-mount-efs-on-your-ec2-instance-and-it-d.txt aws-storage/cf7c5cb836bd aws-storage medium aws, ebs True or False? In EBS gp2 volume type, IP will increase if the disk size increases True. For gp2 volumes, baseline IOPS scales at 3 IOPS per GB (min 100, max 16,000). A larger disk gets more baseline IOPS. gp3 decouples IOPS from size.\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/044-true-or-false-in-ebs-gp2-volume-type-ip-will-incre.txt aws-storage/dbda0219c3bd aws-storage medium aws, ebs, ec2, s3 Give an example of architecture or workflow that involves SQS and EC2 & S3 A website that allows users to upload videos and adds subtitles to them:\n\n1. First the user uploads the video through the web interface which uploads it to an S3 bucket\n2. SQS gets notified with a message on the video location\n3. EC2 instance (or Lambda function) starts to work on adding the subtitles\n4. The video with the subtitles is uploaded to an S3 buckets\n5. SQS gets notified of the result and specifically the video location\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/339-give-an-example-of-architecture-or-workflow-that-i.txt aws-storage/e12e309a72d7 aws-storage medium aws, s3 "Explain ""Multi-part upload""" "[Amazon docs](https://docs.aws.amazon.com/AmazonS3/latest/userguide/mpuoverview.html): ""Multipart upload allows you to upload a single object as a set of parts. Each part is a contiguous portion of the object's data...In general, when your object size reaches 100 MB, you should consider using multipart uploads instead of uploading the object in a single operation.""\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts." projects/knowledge/interview/aws/144-explain-multi-part-upload.txt aws-storage/e21d9ca817e0 aws-storage medium aws, efs What EFS modes are there? * Performance mode\n * General purpose: used mainly for CMS, web serving, ... as it's optimal for latency sensitive applications\n * Max I/O: great for scaling to high levels of throughput and I/O operations per second\n* Throughput mode\n * Bursting: scale throughput based on FS size\n * Provisioned: fixed throughput\n\nRemember: EFS = Elastic File System. NFS-compatible, shared across multiple EC2 instances. Auto-scales, pay per GB stored. Think 'shared network drive.' projects/knowledge/interview/aws/052-what-efs-modes-are-there.txt aws-storage/e41d9653aa87 aws-storage medium aws, ami, ebs, ec2 Describe in high-level the process of creating AMIs 1. Start an EC2 instance\n2. Customized the EC2 instance (install packages, change OS configuration, etc.)\n3. Stop the instance (for avoiding data integrity issues)\n4. Create EBS snapshot and build an AMI\n5. To verify and test the AMI, launch an instance from the AMI\n\nGotcha: S3 bucket names are globally unique across all AWS accounts. Choose descriptive names with your org prefix to avoid conflicts. projects/knowledge/interview/aws/027-describe-in-high-level-the-process-of-creating-ami.txt aws-storage/e522592a0dc2 aws-storage medium aws, efs True or False? EFS is locked into a single availability zone False. EFS can be mounted across multiple availability zones.\n\nRemember: EFS = Elastic File System. NFS-compatible, shared across multiple EC2 instances. Auto-scales, pay per GB stored. Think 'shared network drive.' projects/knowledge/interview/aws/049-true-or-false-efs-is-locked-into-a-single-availabi.txt aws-storage/e64b8c9a4f8a aws-storage medium aws, glacier, lifecycle, s3 Explain the different storage classes in Amazon S3 and their use cases. * Standard: General-purpose storage for frequently accessed data.\n* Infrequent Access (IA): For less frequently accessed data but requires rapid access when needed.\n* Glacier: For long-term archival storage with retrieval times of minutes to hours.\n\nRemember: S3 tiers by cost (high to low): Standard > Intelligent-Tiering > IA > One Zone-IA > Glacier Instant > Glacier Flexible > Glacier Deep Archive. Access speed decreases as cost decreases. projects/knowledge/interview/aws/425-explain-the-different-storage-classes-in-amazon-s3.txt aws-storage/eb846c9d786d aws-storage medium aws, s3, versioning "Explain ""Object Versioning""" When enabled at a bucket level, versioning allows you to upload new version of files, overriding previous version and so be able to easily roll-back and protect your data from being permanently deleted.\n\nRemember: S3 versioning preserves every version of every object. Delete adds a 'delete marker' — the object is recoverable. Combine with lifecycle rules to manage costs. projects/knowledge/interview/aws/145-explain-object-versioning.txt aws-storage/ebe2607cfc5e aws-storage easy aws, efs, s3 What is a bucket in cloud object storage (S3/GCS)? An S3 bucket is a resource which is similar to folders in a file system and allows storing objects, which consist of data.\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/141-what-is-a-bucket.txt aws-storage/ed2038e6dc33 aws-storage hard aws, ebs How to migrate an EBS volume across availability zones? 1. Pause the application\n2. Take a snapshot of the EBS volume\n3. Restore the snapshot in another availability zone\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/387-how-to-migrate-an-ebs-volume-across-availability-z.txt aws-storage/ee3b8c3b53a1 aws-storage hard aws, s3 What's a presigned URL? Since every newly created bucket is by default private it doesn't allows to share files with users. Even if the person who uploaded them tries to view them, it gets denied.\n\nA presigned URL is a way to bypass that and allow sharing the files with users by including the credentials (token) as part of the URL. It can be done for limited time.\n\nRemember: presigned URLs grant temporary access to private S3 objects. The URL includes the signature and expiry. Use for secure file sharing without making objects public. projects/knowledge/interview/aws/149-whats-a-presigned-url.txt aws-storage/ef65044b5261 aws-storage hard aws, ebs, ec2 Is it possible to attach the same EBS volume to multiple EC2 instances? Yes, with multi-attach it's possible to attach a single EBS volume to multiple instances.\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/037-is-it-possible-to-attach-the-same-ebs-volume-to-mu.txt aws-storage/f31a5b5d156b aws-storage medium aws, ebs, ec2 What is Amazon EBS (Elastic Block Store) and when would you use it? "[AWS Docs](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AmazonEBS.html): ""provides block level storage volumes for use with EC2 instances. EBS volumes behave like raw, unformatted block devices.""\n\nRemember: EBS = Elastic Block Store. Network-attached block storage for EC2. Think 'virtual hard drive.' Types: gp3 (general), io2 (high IOPS), st1 (throughput), sc1 (cold)." projects/knowledge/interview/aws/032-explain-amazon-ebs.txt aws-storage/f43b40aced4c aws-storage medium aws, ebs, s3 How to host static website in AWS ? Host a static website on AWS using Amazon S3. Upload your files to an S3 bucket and enable static website hosting in the bucket properties.\n\nRemember: S3 is eventually consistent for overwrite PUTs and DELETEs (as of 2020, S3 provides strong read-after-write consistency for all operations). This was a major change — older docs may say otherwise. projects/knowledge/interview/aws/460-how-to-host-static-website-in-aws.txt aws-storage/f95f7069720b aws-storage medium aws, storage What is the maximum size of an individual S3 object? 5 Terabytes (TB).\n\nName origin: S3 = Simple Storage Service. Object storage with 99.999999999% (11 nines) durability.\n\nRemember: S3 is object storage (key-value), not a filesystem. Objects can be 0 bytes to 5 TB. Use multipart upload for files > 100 MB. projects/knowledge/interview/aws/466-s3-object-max-size.txt\n --- ## Wiki Navigation ### Related Content - [AWS S3 Deep Dive](../../../../library/topics/aws-s3-deep-dive/index.md) (Topic Pack, L1) — AWS S3 Deep Dive