ClearFoundation

- Overview
  - Software RAID
  - Hardware RAID
- Links

Overview

Both software and hardware RAID are supported in ClearOS. If you plan on implementing hardware RAID, please read the section below regarding supported hardware. Before you decide to purchase an expensive hardware RAID controller card, consider the following passage from the experts at O'Reilly

“Software RAID has unfortunately fallen victim to a FUD (fear, uncertainty, doubt) campaign in the system administrator community. I can’t count the number of system administrators whom I’ve heard completely disparage all forms of software RAID, irrespective of platform. Many of these same people have admittedly not used software RAID in several years, if at all.

“Why the stigma? Well, there are a couple of reasons. For one, when software RAID first saw the light of day, computers were still slow and expensive (at least by today’s standards). Offloading a high-performance task like RAID I/O onto a CPU that was likely already heavily overused meant that performing fundamental tasks such as file operations required a tremendous amount of CPU overhead. (…) But today, even multiprocessor systems are both inexpensive and common.” - Derek Vadala - Managing RAID on Linux - O'Reilly

This book is highly recommended and an excellent resource if you plan on using RAID in ClearOS.

Software RAID

You can implement software RAID in ClearOS by selecting the advanced "I will do my own partitioning" option during the installation wizard.

Hardware RAID

Some hardware RAID controller cards are not true hardware controller cards. They are simple IDE controllers with BIOS and drivers to do software RAID. If redundancy is your primary concern, then software RAID will serve you better than a quasi-hardware RAID card. To quote (again) from the Managing RAID on Linux book from O'Reilly:

“The low-end (RAID) controllers are, in essence, software RAID controllers because they rely on the operating system to handle RAID operations and because they store array configuration information on individual component disk. The real value of the controller is in the extra ATA channels.”

Supported hardware RAID cards: