User`s guide
Table Of Contents
- About This Guide
- Kit Contents and System Requirements
- About Your RAID Controller
- Standard RAID Controller Features
- Adding Enhanced Features
- Adding a Battery Backup Module
- Upgrading the Controller Firmware
- About the Adaptec 3085
- About the Adaptec 3405
- About the Adaptec 3805
- About the Adaptec 31205
- About the Adaptec 31605
- About the Adaptec 4000
- About the Adaptec 4800SAS
- About the Adaptec 4805SAS
- About the Adaptec 2420SA
- About the Adaptec 2820SA
- About the Adaptec 2130SLP
- About the Adaptec 2230SLP
- Getting Started
- Installing the Controller and Disk Drives
- Creating a Bootable Array
- Installing the Driver and an Operating System
- Installing the Driver on an Existing Operating System
- Managing Your Storage Space
- Solving Problems
- Introduction to Serial Attached SCSI
- Understanding RAID
- Using the Adaptec RAID Configuration Utility
- Using the Array Configuration Utility for DOS
- Using the Adaptec Flash Utility
- Adaptec Serial Controller LED and I2C Connector Reference
- Adaptec 2420SA Activity LED and I2C Connector Specification
- Adaptec 2820SA Activity LED and I2C Connector Specification
- Adaptec 3085 LED and I2C Connector Specification
- Adaptec 3405 LED and I2C Connector Specification
- Adaptec 3805 LED and I2C Connector Specification
- Adaptec 31205 LED and I2C Connector Specification
- Adaptec 31605 LED and I2C Connector Specification
- Adaptec 4800SAS LED and I2C Connector Specification
- Adaptec 4805SAS LED and I2C Connector Specification
- Safety Information
- Technical Specifications
- Index
Appendix B: Understanding RAID ● 81
RAID 50 Arrays
A RAID 50 array is built from six to forty-eight disk drives configured as two or more RAID 5
arrays, and stripes stored data and parity data across all disk drives in both RAID 5 arrays. (For
more information, see RAID 5 Arrays on page 79.)
Note:
Because they support four disk drives only, the Adaptec 2420SA RAID controller can’t
support RAID 50 arrays.
The parity data provides data protection, and striping improves performance. RAID 50 arrays
also provide high data transfer speeds.
Drive segment size is limited to the size of the smallest disk drive in the array. For example,
three 250 GB disk drives and three 400 GB disk drives comprise two equal-sized RAID 5 arrays
with 500 GB of stored data and 250 GB of parity data. The RAID 50 array can therefore contain
1000 GB (2 x 500 GB) of stored data and 500 GB of parity data.
In this figure, P represents the distributed parity data.
RAID 5
B
RAID 50
Logical Drive
=
1000 GB
plus Parity
RAID 5
A
Each RAID 5 Logical Drive has
500 GB Data Storage
250 GB Parity Data
Drive 1
250 GB
Drive 2
250 GB
Drive 3
250 GB
Drive 4
400 GB
Drive 5
400 GB
Drive 6
400 GB
1, 5, P 3, P, 9 P, 7, 11 2, 6, P 4, P, 10 P, 8, 12
Total Unused
Space = 150 GB