All About Hardware RAID

Hardware RAID is the best way to add fast and reliable storage to your computer or server.

This article will explore some concepts regarding hardware RAID by comparing two PCI IDE RAID Cards, the Adaptec 2400A, and the 3-Ware Escalade 7506-8.

IDE? Why?
These are the latest and greatest in IDE RAID technology. In the current year of 2009 one might wonder how valid this information is. Actually, it is extremely valid beacuse while the medium will continue to change, the concepts surrounding RAID and disk based storage have not changed.

You can always just use a bunch of SATA to IDE adapters to make an old IDE system work with SATA drives:


RAID in a nutshell
RAID stands for Redundant Array of Independant Drives. It means multiple hard drives work together to make one drive. There are many different modes of RAID, and each provide different levels of enhanced reliability and peformance.

RAID Modes
RAID 1 - Striping = High Speed, but Low Reliability
This is using multiple drives to increase speed. All of your data is spanned across all of the drives. The mor drives you have, the faster the array. But if a single drive fails, the whole array becomes useless.

RAID 0 - Mirroring = Marginal Speed incrase, High Reliability
This mode uses multiple drives to keep backups of your data. All of your data is on all of the drives. If a single drive fails, you still have all of your data on another drive.

RAID 5 - Distributed Parity = High Speed, High Reliability
This is the best overall RAID type for a typical small business storage system. All of your data is spanned across all of the drive, like in RAID 1, but backup (parity) data is also stored on a drive. One drive can fail and your data will still be available.

If you have an Adaptec 2400A controller, and you only see 128GB available, you need up upgrade your firmware.

Here you can see my controller has firmware version 370L and you can only see 128GB of my 300GB drive.


After upgrading the firmware to version 3A0L, I can utilize all 300GB: