Difference between RAID 1 and RAID 5 on a QNAP NAS
RAID 1:
Overview
- RAID 1, also known as "Mirroring," is a data redundancy technique that creates an exact copy of data on two identical drives.
- Data is written simultaneously onto both drives, resulting in real-time duplication.
- A minimum of 2 drives is required for RAID 1.
Advantages
- High data redundancy: If one drive fails, the data can still be accessed and recovered from the remaining drive.
- Fast data read performance: Since the data is duplicated on both drives, read operations can occur simultaneously, improving performance.
Disadvantages
- Inefficient use of storage capacity: The usable storage capacity is only half of the total capacity due to the mirroring process.
- No improvement in write performance: Write operations performance remains similar to that of a single drive.
RAID 5:
Overview
- RAID 5 utilizes striping with parity to store data across multiple drives. It requires a minimum of 3 drives.
- Data and parity information are distributed across all drives in the array.
- Parity information provides fault tolerance in case of a drive failure. It can reconstruct lost data from the remaining drives.
Advantages
- High storage efficiency: Only one drive's worth of capacity is used for parity, resulting in a better capacity utilization compared to RAID 1.
- Tolerant to drive failures: RAID 5 can withstand the loss of a single drive without data loss.
- Good overall performance: It offers a good balance between data redundancy and performance, especially for read operations.
Disadvantages
- Lower write performance: Unlike RAID 1, RAID 5 requires additional calculations for parity, impacting write performance.
- Higher risk during drive rebuild: During the rebuild process after a failed drive replacement, if another drive fails, data loss can occur.
