Storage system

Question 2

What is object storage?

Answer 2

Object storage stores data as objects with metadata and unique identifiers, rather than hierarchical file systems. Examples: AWS S3, Google Cloud Storage. Ideal for unstructured data like images and videos.

Question 3

What is block storage?

Answer 3

Block storage divides data into fixed-size blocks with unique addresses. It’s fast and used for databases and VMs. Examples: AWS EBS, Azure Disk Storage. Allows random access and low latency.

Question 4

What is file storage?

Answer 4

File storage organizes data in hierarchical directory structure with folders and files. Used for shared access scenarios. Examples: NFS, SMB/CIFS, AWS EFS. Familiar interface but less scalable than object storage.

Question 5

What is the difference between hot and cold storage?

Answer 5

Hot storage: frequently accessed data, expensive, fast access (SSD). Cold storage: rarely accessed data, cheap, slower access (archival systems like AWS Glacier). Used for cost optimization.

Question 6

What is data durability?

Answer 6

Durability is the likelihood that data will not be lost over time. Cloud providers offer high durability (99.999999999% or 11 nines) through replication across multiple data centers.

Question 7

What is RAID?

Answer 7

RAID (Redundant Array of Independent Disks) combines multiple disks for performance or redundancy. RAID 0: striping (speed). RAID 1: mirroring (redundancy). RAID 5/6: striping with parity (balance).

Question 8

What is a distributed file system?

Answer 8

A distributed file system spreads data across multiple servers while appearing as single storage. Examples: HDFS (Hadoop), GlusterFS, Ceph. Enables massive scalability and fault tolerance.

Question 9

What is data replication vs backup?

Answer 9

Replication: continuous copying of live data to multiple locations for availability. Backup: periodic snapshots for disaster recovery. Replication is real-time; backups are point-in-time.

Question 10

What is erasure coding?

Answer 10

Erasure coding splits data into fragments, expands with redundant pieces, and distributes across locations. More storage-efficient than replication while maintaining fault tolerance.

Question 11

What is eventual consistency in storage?

Answer 11

Eventual consistency means replicas may temporarily have different values but will eventually converge. Trades immediate consistency for higher availability and performance in distributed storage.