- LPU MCA Semester 1
- CAP470
- Unit 5
CAP470 · Unit 5: Cloud access, storage and file systems
Storage systems in cloud, storage types and storage volumes
11 practice questions · in the ETE syllabus
Key points
- Object, block and file storage suit different uses
- A volume is a virtual disk attached to a VM
- IOPS measures operations per second
- Storage is billed per GB per month and replicated
Cloud providers offer three main kinds of storage.
| Type | How data is organised | Typical use |
|---|---|---|
| Object | Objects with metadata and a unique key in buckets, accessed over HTTP | Photos, videos, backups, static websites |
| Block | Raw volumes that behave like a disk | Databases, operating system disks |
| File | Folders and files shared over a network (NFS, SMB) | Shared team folders |
A storage volume is a virtual disk provisioned from the provider's storage and attached to a virtual machine; it can be detached, resized and snapshotted. IOPS (input/output operations per second) measures how many reads and writes a volume can handle, while latency is the delay of one request and durability is the chance data is not lost.
Cloud storage is billed by usage, for example price per GB per month, so 500 GB for 3 months at 0.02 dollars per GB-month costs 500 x 0.02 x 3 = 30 dollars. Providers also keep several copies of data for durability, so three copies of 200 GB use 600 GB of raw capacity.
Exam trap: object storage is not a disk. Choose block storage for databases and object storage for large collections of files served by URL.
Try two questions
What is a storage volume in a cloud platform?
- A physical disk that the customer must install in the data centre
- A backup tape stored in a safe at the provider's office
- A virtual disk provisioned from the provider's storage that can be attached to a virtual machine
- A folder that exists only on the user's own laptop
Show the answer
C. Volumes such as Amazon EBS behave like disks that can be attached, detached and resized.
Why not A: The customer does not handle physical disks in a public cloud.
Why not B: A volume is a live disk, not a backup tape.
Why not D: A volume lives on the provider's storage, not on a laptop.
Which storage type presents a raw volume that behaves like a hard disk attached to a server?
- Object storage
- File storage
- Block storage
- Archive storage
Show the answer
C. Block volumes are formatted by the operating system and suit databases.
Why not A: Object storage is accessed through an API as whole objects.
Why not B: File storage presents a shared folder hierarchy.
Why not D: Archive storage is for rarely accessed data.