Understanding RAID
This topic describes the work principles of non-RAID (disks work independently), RAID1, and RAID5 and differences among non-RAID, RAID1, and RAID5. This topic also describes the disk mode, disk space usage supported by each VCN5X0 model.
VCN510 supports non-RAID and RAID1 modes. VCN520 and VCN540 support non-RAID and RAID5 modes. Table 1 describes the disk modes.
Disk Mode | Description |
|---|---|
NON-RAID | Figure 1 shows the non-RAID mode. In this mode, disks work independently. Data is stored to all disks by file block (1 GB). The disk usage is high, but the data storage reliability is lower than that in RAID5 or RAID1 mode. |
RAID1 | Figure 2 shows the RAID1 mode. In RAID1 mode, two disks are required for mutual backup. Data is stored in two disks by file block and backed up to the other disk simultaneously. The data storage reliability is high, but the disk usage is lower than that in non-RAID mode. |
RAID5 | Figure 3 shows the RAID5 mode. In RAID5 mode, at least three disks are required. All the disks are created as a RAID5 group. The data file blocks (1 GB) are divided into N copies (N = Number of disks - 1). Then, the data file and parity check information form a data strip, which is stored in each di of the RAID5. The parity check information and data are stored in different disks. When a disk in RAID5 is damaged, use the data and parity check information in remaining disks to restore the data in the damaged disk. The data storage reliability is high, but the disk usage is lower than that in non-RAID mode. RAID5 has the following two configuration modes:
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