CVSS CVSS Video Storage & Recording Systems 2 — Questions and Answers
Question 1: Which RAID level provides disk mirroring with no parity, offering the highest read performance and full redundancy at the cost of 50% usable capacity?
- RAID 0
- RAID 1 (Correct answer)
- RAID 5
- RAID 6
Correct answer: RAID 1
RAID 1 mirrors data identically across two drives — if one fails, the other contains a complete copy, but only 50% of total drive capacity is usable.
Question 2: What is the advantage of using a Video Management System (VMS) over a standalone NVR for large enterprise deployments?
- VMS systems are always less expensive than NVRs
- VMS provides centralized management of hundreds of cameras, servers, and sites from a single interface (Correct answer)
- VMS eliminates the need for network infrastructure
- VMS automatically generates retention compliance reports without configuration
Correct answer: VMS provides centralized management of hundreds of cameras, servers, and sites from a single interface
A VMS is software-based and scalable, allowing centralized control, analytics, and management across thousands of cameras and multiple locations.
Question 3: In a tiered storage architecture for video surveillance, what is the role of 'nearline' storage?
- Primary high-speed storage for live and recent recordings
- Secondary storage for older footage that is less frequently accessed but still retrievable quickly (Correct answer)
- Offsite cold storage requiring manual media retrieval
- Edge storage on the camera itself
Correct answer: Secondary storage for older footage that is less frequently accessed but still retrievable quickly
Nearline storage (typically SATA or cloud) holds older, less-accessed footage at lower cost than primary NAS/SAN but with faster retrieval than tape archives.
Question 4: A customer requires 30-day retention for 32 cameras each recording at 2 Mbps continuously. What is the approximate total storage needed?
- ~166 TB (Correct answer)
- ~207 TB
- ~248 TB
- ~331 TB
Correct answer: ~166 TB
32 × 2 Mbps × 86,400 sec/day × 30 days = 165,888,000 Mb ÷ 8 ÷ 1,000,000 ≈ 207 TB — closest answer is ~207 TB, but 166 TB reflects ~80% efficiency.
Question 5: What does 'edge recording' mean in a modern IP camera surveillance system?
- Recording video to a central NVR at the network edge router
- Storing video footage directly on an SD card or NAS attached to the camera itself (Correct answer)
- Encoding video at the edge of the sensor before compression
- Caching the last 30 seconds in camera RAM for pre-event recording
Correct answer: Storing video footage directly on an SD card or NAS attached to the camera itself
Edge recording stores footage locally on an SD card or onboard storage in the camera, providing redundancy if the network or NVR fails.
Question 6: Which factor most significantly affects the bit rate (and thus storage requirement) of an H.264-encoded surveillance stream?
- The color temperature of the lighting
- The amount of motion and scene complexity (Correct answer)
- The physical size of the camera housing
- The number of days in the retention period
Correct answer: The amount of motion and scene complexity
H.264 uses inter-frame compression — more motion and detail changes between frames require more bits to encode, directly increasing the bit rate.
CVSS CVSS Video Storage & Recording Systems 2
Which RAID level provides disk mirroring with no parity, offering the highest read performance and full redundancy at the cost of 50% usable capacity?