3.4 Raid

Question 1

What is RAID?

Answer 1

RAID (Redundant Array of Independent Disks) is a method of combining multiple drives to improve performance and/or provide redundancy.

RAID configurations can vary in terms of performance and redundancy.

Question 2

Is RAID a replacement for backups?

Answer 2

No, RAID provides redundancy but is not a backup solution; separate backups are still essential.

Backups are necessary to protect against data loss from other factors.

Question 3

What is RAID 0 and how does it work?

Answer 3

RAID 0 splits (stripes) data across at least two drives, improving write and read performance.

RAID 0 enhances speed but does not provide redundancy.

Question 4

Does RAID 0 provide redundancy?

Answer 4

No; if one drive fails, all data is lost.

This makes RAID 0 unsuitable for critical data storage.

Question 5

What is RAID 1 and how does it work?

Answer 5

RAID 1 duplicates (mirrors) data across at least two drives, creating an exact copy on each.

This setup ensures data availability even if one drive fails.

Question 6

What are the advantages and disadvantages of RAID 1?

Answer 6

• Advantage: full redundancy; system continues if one drive fails
• Disadvantage: uses twice the storage capacity

RAID 1 is ideal for critical data but at the cost of storage efficiency.

Question 7

How does RAID 5 work?

Answer 7

Data is striped across multiple drives with a single distributed parity block, allowing recovery if one drive fails.

RAID 5 balances performance and redundancy.

Question 8

What is a downside of RAID 5?

Answer 8

Requires CPU overhead for parity calculations.

This can impact performance, especially under heavy loads.

Question 9

Minimum number of drives for RAID 5?

Answer 9

Three drives.

This is necessary to implement the parity feature.

Question 10

How does RAID 6 differ from RAID 5?

Answer 10

RAID 6 uses two parity blocks instead of one, allowing two drives to fail without data loss.

This provides an extra layer of protection compared to RAID 5.

Question 11

What is a trade-off of RAID 6?

Answer 11

Additional storage space is needed for the second parity block.

This can reduce the overall usable capacity of the RAID array.

Question 12

Minimum number of drives for RAID 6?

Answer 12

Four drives.

This is required to accommodate the dual parity.

Question 13

How does RAID 10 work?

Answer 13

RAID 10 combines RAID 0 (striping) and RAID 1 (mirroring). Data is mirrored, and mirrored sets are striped for performance and redundancy.

This configuration offers both speed and data protection.

Question 14

What is the minimum number of drives for RAID 10?

Answer 14

Four drives.

This is necessary to create at least one mirrored pair.

Question 15

What are the advantages of RAID 10?

Answer 15

• High redundancy
• Good performance
• Multiple drives can fail without data loss, depending on which drives fail

RAID 10 is often preferred for critical applications requiring both speed and reliability.