先决条件– RAID，RAID级别
1. RAID 1：
RAID 1也称为数据的镜像配置，因为它将数据从驱动器1复制到驱动器2。在RAID 1中，一个驱动器用于存储数据，另一个驱动器充当已存储数据的镜像。如果发生任何故障，此级别的RAID可提供100％的数据冗余。
优势 –
它具有良好的容错能力，即即使一个磁盘出现故障也可以维护功能。
坏处 –
这很昂贵，因为镜像需要额外的驱动器。
2. RAID 5：
在RAID 5中，将数据平均分配到所有磁盘中，所需的最小物理磁盘数为3。与RAID 1相比，RAID 5的主要优点是不需要大空间，在恢复时支持数据访问，并且数据安全性高。 。 RAID 5通常适合中级应用程序。
优势 –
引入RAID 5是为了使随机写入性能更好。
坏处 –
RAID 5最多可以恢复1个磁盘故障(由于奇偶校验的工作方式)。如果多个磁盘发生故障，则无法恢复数据。
RAID 1和RAID 5之间的区别：
| S.No. | RAID 1 | RAID 5 |
|---|---|---|
| 1. | RAID 1 stands for Redundant Array of Independent Disk level 1. | RAID 5 stands for Redundant Array of Independent Disk level 5. |
| 2. | In RAID 1, data is not split in the disks. | In RAID 5, data is equally divided in all disks. |
| 3. | The write speed of RAID 1 is slower than RAID 5. | The write speed of RAID 5 is better than RAID 1. |
| 4. | In RAID 1, minimum number of physical disks needed is 2. | In RAID 5, minimum number of physical disks needed is 3. |
| 5. | RAID 1 supports mirroring and redundancy. | RAID 5 does not support mirroring and redundancy. |
| 6. | Data accessing rate is low in RAID 1. | Data accessing rate is high in RAID 5. |
| 7. | In RAID 1, large space is needed for mirror spacing. | In RAID 5, large space is not needed. |
| 8. | In RAID 1, we cannot access data at the time of recovery. | In RAID 5, data can be accessed while recovering data from failure. |
| 9. | Security of data is low in RAID 1. | Security of data is very high in RAID 5. |
| 10. | RAID 1 is best suited for high-end level of applications. | RAID 5 is generally suited for medium level of applications. |