CST CST Storage & Retention Management 2 — Questions and Answers
Question 1: What does RAID stand for in the context of NVR storage?
- Redundant Array of Independent Disks (Correct answer)
- Remote Access and Integrated Data
- Recording Archive and Index Database
- Real-time Automated Image Delivery
Correct answer: Redundant Array of Independent Disks
RAID (Redundant Array of Independent Disks) combines multiple drives to provide data redundancy, performance, or both.
Question 2: Which RAID level provides mirroring, meaning data is written identically to two drives simultaneously?
- RAID 0
- RAID 1 (Correct answer)
- RAID 5
- RAID 6
Correct answer: RAID 1
RAID 1 mirrors data across two drives so that if one fails, the other contains an identical copy ensuring no data loss.
Question 3: What is the key disadvantage of RAID 0 for surveillance storage?
- It is too slow for video recording
- It provides no redundancy — a single drive failure causes total data loss (Correct answer)
- It requires a minimum of six drives
- It cannot be used with NVRs
Correct answer: It provides no redundancy — a single drive failure causes total data loss
RAID 0 stripes data across drives for performance but has zero fault tolerance — one drive failure loses all data.
Question 4: RAID 5 requires a minimum of how many drives?
- 2
- 3 (Correct answer)
- 4
- 6
Correct answer: 3
RAID 5 requires at least 3 drives to distribute parity data across all drives while maintaining read/write performance.
Question 5: What is a hot spare drive in a RAID array used for surveillance?
- An extra drive kept powered and ready to automatically replace a failed drive (Correct answer)
- A drive used only for software backups
- A spare drive stored in a warehouse for future expansion
- A drive that records at a higher frame rate
Correct answer: An extra drive kept powered and ready to automatically replace a failed drive
A hot spare is an idle drive in the array that automatically begins rebuilding data when another drive fails, minimizing downtime.
Question 6: Which storage technology is increasingly used in surveillance NVRs because it has no moving parts and faster read speeds?
- Magnetic tape
- Optical disc (Blu-ray)
- Solid-state drive (SSD) (Correct answer)
- Floppy disk
Correct answer: Solid-state drive (SSD)
SSDs offer faster read/write speeds, lower latency, and greater shock resistance compared to traditional HDDs for surveillance applications.
CST CST Storage & Retention Management 2
What does RAID stand for in the context of NVR storage?