What is Amazon S3?
Simple Storage Service – object storage. Stores any file type up to 5TB per object. Objects stored in buckets with globally unique names. 99.999999999% (11 nines) durability. Not mountable or bootable.
What are the S3 storage classes and their use cases?
Standard: frequent access, active data. | Intelligent-Tiering: unknown/changing access, auto-moves between tiers. | Standard-IA: infrequent access, disaster recovery/backups. | One Zone-IA: infrequent, secondary backups (single AZ). | Glacier Instant Retrieval: rare access but millisecond retrieval. | Glacier Flexible Retrieval: archives, 3-5hr retrieval. | Glacier Deep Archive: cheapest, 12-48hr retrieval, compliance.
What is S3 Intelligent-Tiering?
Automatically moves objects between access tiers based on changing access patterns. No retrieval fees. Ideal when access frequency is unknown or variable.
What is the retrieval time for each Glacier tier?
Glacier Instant Retrieval: milliseconds. | Glacier Flexible Retrieval: Expedited 1-5 min, Standard 3-5 hrs, Bulk 5-12 hrs. | Glacier Deep Archive: 12-48 hours.
What are the key S3 features beyond storage?
Versioning (multiple object versions), Lifecycle policies (auto-move/delete objects), Cross-Region Replication (CRR), Same-Region Replication (SRR), Static website hosting, S3 Transfer Acceleration (fast uploads via CloudFront edge locations).
What is Amazon EBS?
Elastic Block Store – block storage for EC2 instances (like a virtual hard drive). Persists independently from EC2 lifecycle. AZ-specific (must be in same AZ as EC2). Supports snapshots backed to S3. Can be mounted and booted.
What are the EBS volume types?
gp3/gp2: General Purpose SSD (general workloads, boot volumes). | io2 Block Express/io1: Provisioned IOPS SSD (high-performance/I-O intensive DBs, up to 256,000 IOPS). | st1: Throughput Optimized HDD (big data, data warehouses). | sc1: Cold HDD (infrequently accessed, lowest cost HDD).
What is Amazon EFS?
Elastic File System – managed NFS (Network File System) for Linux. Shared storage – multiple EC2 instances can mount simultaneously. Scales automatically across multiple AZs. Cannot be used as boot volume. More expensive than EBS.
EFS vs EBS – full comparison?
EFS: NFS protocol, multiple instances simultaneously, Linux only, multi-AZ, auto-scaling, cannot boot. | EBS: block (iSCSI), mostly single instance, Linux and Windows, single AZ, manually provisioned, can boot.
What is an EC2 Instance Store?
Temporary block-level storage physically attached to the host. Data is lost if the instance is stopped or terminated. Very high performance, but not persistent.
What is AWS Storage Gateway?
Hybrid storage service connecting on-premises environments to AWS cloud storage. Types: File Gateway, Volume Gateway, Tape Gateway.
What is the AWS Snow Family?
Physical devices for large-scale data transfer to/from AWS. | Snowcone: smallest (8TB SSD or HDD), rugged, edge computing. | Snowball Edge: 80-210TB, edge computing capabilities. | Snowmobile: 100PB, a 45-foot ruggedised shipping container – exabyte-scale migrations.
What are the 3 types of storage (object, block, file) and their AWS services?
Object storage: Amazon S3 – flat structure, no mounting, good for media/backups/static sites. | Block storage: Amazon EBS – mountable/bootable, AZ-specific. | File storage: Amazon EFS – hierarchical, shared NFS mount, multi-AZ.
What is Amazon EC2?
Elastic Compute Cloud – virtual machines (IaaS) in the cloud. Full control over OS, applications, and configuration. Customer is responsible for OS patches, security configurations. Can be provisioned in minutes.
What are the EC2 instance families?
General Purpose (t, m): balanced compute/memory/network. | Compute Optimised (c): high-performance CPUs, batch processing, ML. | Memory Optimised (r, x): large in-memory datasets, databases. | Storage Optimised (i, d, h): high I/O sequential read/write, big data. | Accelerated Computing (p, g, f): GPU/FPGA, graphics, data pattern matching.
How do you decode an EC2 instance type name like t3.micro?
t = family (General Purpose), 3 = generation, micro = size.
What is an AMI (Amazon Machine Image)?
A template for launching an EC2 instance – defines the OS, pre-installed software, and configuration. AWS provides many AMIs; you can also create custom AMIs.
What are EC2 Key Pairs?
Used for SSH authentication into EC2 instances. A public/private key pair – public key stored on instance, private key (.pem file) kept by user.
What is EC2 User Data?
A script that runs automatically on the instance at first boot. Used to install software, configure settings, or perform startup tasks.
What is EC2 Instance Metadata?
Data about the running instance accessible at the IP address 169.254.169.254. Contains instance ID, instance type, IAM role credentials, etc.
What is an Elastic IP?
A static IPv4 address for dynamic cloud computing. Free when attached to a running instance; charged ($0.005/hr) when unattached.
What are EC2 Placement Groups?
Control how instances are placed on underlying hardware. Types: Cluster (low latency, same AZ), Spread (different hardware, max availability), Partition (groups of instances on different hardware).
What is an Auto Scaling Group (ASG)?
Automatically adjusts EC2 capacity based on demand. Uses a Launch Template to define instance specs. Scaling policies: Target Tracking (maintain metric), Step Scaling (scale by amounts), Scheduled (at specific times). Auto-replaces unhealthy instances.
What are the EC2 pricing models?
On-Demand: hourly/second, no commitment. | Reserved (1 or 3yr): up to 72% off. | Spot: up to 90% off, interruptible with 2-min warning. | Savings Plans: flexible commitment, up to 66% off. | Dedicated Host: dedicated physical server, up to 70% with RI. | Dedicated Instance: dedicated hardware, slightly less control than Dedicated Host.
