Users Guide

• RAID 6 — Stripes data across the physical disks, and uses two sets of parity information for additional data

redundancy. If one or two physical disks fail, the data can be rebuilt using the parity information. RAID 6 offers

good data redundancy and read performance but slower write performance.

• RAID 10 — Combines mirrored physical disks with data striping. If a physical disk fails, data can be rebuilt using

the mirrored data. RAID 10 offers good read and write performance with good data redundancy.

• RAID 50 — A dual-level array that uses multiple RAID 5 sets in a single array. A single physical disk failure can

occur in each of the RAID 5 without any loss of data on the entire array. Although the RAID 50 has increased

write performance, its performance decreases, data or program access gets slower, and transfer speeds on the

array are affected when a physical disk fails and reconstruction takes place.

• RAID 60 — Combines the straight block level striping of RAID 0 with the distributed double parity of RAID 6. The

system must have at least eight physical disks to use RAID 60. Failures while a single physical disk is rebuilding

in one RAID 6 set do not lead to data loss. RAID 60 has improved fault tolerance because more than two physical

disks on either span must fail for data loss to occur.

Minimum Disk Requirement for Different RAID Levels

Table 10. : RAID Level and Number of Disks

RAID Level Minimum Number of Disks

0 1*

1 2

5 3

6 4

10 4

50 6

60 8

* For S110 RAID controller, a minimum of 2 disks are required.

Selecting Physical Disks

Use the Select Physical Disks screen to select the physical disks to be used for the virtual disk and select the physical

disk related properties.

The number of physical disks required for the virtual disk varies depending on the RAID level. The minimum and

maximum numbers of physical disks required for the RAID level are displayed on the screen.

• From the Protocol drop-down menu, select the protocol for the disk pool: Serial Attached SCSI (SAS) or Serial

ATA (SATA). SAS drives are used for high performance, and SATA drives provide a more cost-effective solution.

A disk pool is a logical grouping of physical disks on which one or more virtual disks can be created. The

protocol is the type of technology used to implement RAID.

• From the Media Type drop-down menu, select the media type for the disk pool: Hard Disk Drives (HDD) or Solid

State Disks (SSD). HDDs use traditional rotational magnetic media for data storage, and SSDs implement flash

memory for data storage.

• From the Select Span Length drop-down menu, select the span length. The span length value refers to the

number of physical disks included in each span. Span length applies only to RAID 10, RAID 50, and RAID 60. The

Select Span Length drop‑down menu is active only if the user has selected RAID-10, RAID-50, or RAID 60.

• Select the physical disks using the check boxes at the bottom of the screen. Your physical disk selection must

meet the requirements of the RAID level and span length. To select all of the physical disks, click Select All.