CompTIA Linux+ (XK0-006)System ManagementHard
A technician is preparing a new Linux server for a database application that requires high-performance, redundant storage. They have four new 1TB physical disks (/dev/sdb, /dev/sdc, /dev/sdd, /dev/sde) and plan to use RAID 10. What is the maximum usable storage capacity for this RAID 10 array?
- A2 TB
- B4 TB
- C1 TB
- D3 TB
Show answer & explanationAnswer & explanation
Correct answer: A. 2 TB
RAID 10 (or RAID 1+0) requires an even number of disks, typically at least four. It stripes data across mirrored pairs. With four 1TB disks, you get two 1TB mirrored pairs. The usable capacity is the sum of the capacities of the mirrored pairs, so 1TB + 1TB = 2TB.
Why the other options are wrong
- B. This would be the capacity of a RAID 0 array with four disks, which offers no redundancy.
- C. This would be the capacity of a single disk or a RAID 1 with two disks.
- D. This is incorrect for RAID 10 with four disks.
RAID 10 (RAID 1+0)
A nested RAID level that combines striping (RAID 0) and mirroring (RAID 1). It creates mirrored pairs of disks, and then stripes data across these mirrors. It requires a minimum of four disks and provides both performance and redundancy.
- Minimum 4 disks, must be an even number.
- Usable capacity is 50% of total raw capacity.
- Offers good performance (from striping) and excellent redundancy (from mirroring).
- Can sustain multiple disk failures, as long as they are not in the same mirrored pair.
Memory trick: RAID 10: Mirror then Stripe, Half the Space, Double the Speed.