Appendix B: Understanding RAID 66

Drive segment size is limited to the size of the smallest disk drive in the array. For instance, an array with two 250 GB disk drives and two 400 GB disk drives can create a RAID 0 drive segment of 250 GB, for a total of 1000 GB for the volume, as shown in the following figure.

Disk Drive 1

Drive Segment Size (Smallest Disk Drive)

 

250 GB

 

 

 

 

Disk Drive 2

 

 

 

 

 

 

250 GB

 

 

 

 

 

 

Disk Drive 1

1

5 ...

997

 

 

 

Disk Drive 3

 

Disk Drive 2

2

 

998

 

 

6 ...

400 GB

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Disk Drive 3

3

7 ...

999

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Unused Space: 150 GB

 

 

 

 

Not Used

Disk Drive 4

400 GB

Disk Drive 4 4

8 ...

1000

 

 

 

 

Unused Space: 150 GB

 

 

 

 

 

 

 

 

 

Not Used

Disk Drives in Logical Drive

RAID 0 Logical Drive = 1000 GB

RAID 1 Arrays

A RAID 1 array is built from two disk drives, where one disk drive is a mirror of the other (the same data is stored on each disk drive). Compared to independent disk drives, RAID 1 arrays provide improved performance, with twice the read rate and an equal write rate of single disks. However, capacity is only 50 percent of independent disk drives.

If the RAID 1 array is built from different-sized disk drives, the free space, drive segment size is the size of the smaller disk drive, as shown in the following figure.

 

 

Drive Segment Size (Smaller Disk Drive)

Disk Drive 1

250 GB

 

 

 

 

Disk Drive 1

1 – 250

Disk Drive 2

400 GB

Disk Drive 2

1 – 250

 

 

Unused Space: 150 GB

Not Used

Disk Drives in Logical Drive

RAID 1 Logical Drive = 250 GB

RAID 10 Arrays

A RAID 10 array is built from two or more equal-sized RAID 1 arrays. Adaptec RAID controllers support a maximum number of 48 disk drives in a RAID 10 array.

Data in a RAID 10 array is both striped and mirrored. Mirroring provides data protection, and striping improves performance.

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Adaptec 48300, 58300, 44300, 1220SA, 1420SA, 1225SA, 1430SA manual RAID 1 Arrays, RAID 10 Arrays

1430SA, 1225SA, 1420SA, 1220SA, 48300 specifications

Adaptec, a prominent name in the world of storage solutions, offers a diverse array of RAID controller cards aimed at enhancing data storage and management in both consumer and enterprise markets. Among its acclaimed products are the Adaptec 1220SA, 1430SA, 44300, 1225SA, and 1420SA. These cards ensure increased data protection, improved performance, and greater scalability.

The Adaptec 1220SA is a robust SATA RAID controller designed for small to medium-sized businesses. It supports RAID levels 0, 1, 1E, 5, and 10, providing flexibility for users to optimize data redundancy and performance. With the capability of handling up to four SATA drives, it guarantees an efficient and reliable setup while minimizing potential data loss. The controller also features an intuitive web-based management interface, making it easier to administer and configure.

The Adaptec 1430SA extends similar functionality with enhanced features. It is designed to accommodate up to eight SATA drives and supports the latest 3 Gbps SATA technology. This model includes optional battery backup for preserving critical data during unexpected power outages, ensuring that users maintain data integrity and protection at all times.

In the enterprise domain, the Adaptec 44300 shines as a high-performance RAID controller. It offers support for 12 SATA drives, which allows for expansive storage scalability, crucial for data-intensive applications. The advanced RAID features include support for RAID 6, providing dual parity data protection. The controller is built with a powerful processor and memory, allowing for faster data processing and enhanced throughput.

The Adaptec 1225SA is another noteworthy model. Designed for entry-level RAID applications, it offers a balanced combination of performance and reliability. Supporting up to four SATA drives, the 1225SA is particularly well-suited for environments where uptime is critical, delivering functionalities such as hot-swapping. This feature allows users to replace failed drives without shutting down the system, significantly reducing downtime.

Lastly, the Adaptec 1420SA caters to users who require a cost-effective but reliable storage solution. With support for RAID 0, 1, and JBOD, it is a versatile option for enthusiasts and small businesses. The controller can manage up to two SATA drives, making it ideal for basic applications where simplicity and efficiency are paramount.

Collectively, these Adaptec controllers showcase cutting-edge RAID technology and storage management features, reinforcing their position as reliable options for users ranging from home users to enterprise-level organizations seeking optimal data storage solutions.