Set the RAID level

Redundant Array of Independent Disks (RAID) is designed to improve read/write performance and fault tolerance. A RAID array offers faster transfer than a single disk, thus significantly increasing the data throughput of the storage system.

You can manage a RAID array in the way of managing independent disks or logical storage units, and can set the RAID level when you purchase an EPC instance or when you reinstall the system based on business demands.

RAID levels are described as follows:

• RAID 1: Ensures data security through data mirroring. The I/O performance is equal to that of a single disk, and the storage utilization is 50%. RAID 1 is suitable for scenarios with high requirements on data security.
• RAID 10 (recommended): Combines data striping of RAID 0 and mirroring-based redundancy of RAID 1. RAID 10 offers a high read/write speed, implements mirroring-based data protection, and provides storage utilization of 50%. RAID 10 is the commonly used method.
• RAID 5: Uses parity and data striping, with high I/O performance and storage utilization of over 50%. The security of RAID 5 is slightly lower than that of RAID 10 and RAID 1. RAID 5 is suitable for scenarios where you have more reads and fewer writes, and offers the best compromise among performance, data redundancy, and cost.
• RAID 50: Combines parity verification of RAID 5 and data striping of RAID 0. RAID 50 can provide high data security while ensuring storage I/O performance. It provides a high storage utilization of N-2/N.
• Single-disk RAID 0: Adopts data striping. It provides the highest I/O performance and achieves disk utilization of 100%. However, it does not provide redundancy guarantee, and therefore cannot be used in scenarios with high requirements on data security.

Set the RAID level when you purchase an EPC instance

When you purchase an EPC instance, you must set the Data Disk RAID parameter in the Select Image step. For more information, see Create an EPC instance.

Set the RAID level when you reinstall the system

When you reinstall the system for an EPC instance, you can set Data Disk RAID. Note that this operation will format the disk, so you must back up the data in advance.

For details of system reinstallation, see Install an operating system.