5 Steps For an Easy RAID 1 Setup

The most common way to set up multiple storage drives is to configure a RAID array. Using RAID to combine multiple drives into a larger virtual drive will generally keep systems up and running despite hardware failure. However, RAID can be cumbersome to setup and unwieldy to manage. For home offices and small businesses interested in adding data mirroring or data-loss-prevention to their systems, RAID's complexity is an obstacle.

It is important to remember that RAID is not a substitute for a backup strategy. While some RAID levels will protect against data loss in case of drive failure, it will not protect against deletions, manual or automated. A user can accidentally (or maliciously) delete a file, and in a RAID setup, the file will also disappear from the mirror. That said, RAID keeps systems up and running, improves performance, and offers data redundancy.

For this TechBuilder recipe, the Channel Test Center looked for an easy and affordable RAID solution for small businesses and home office. The selected offering, Stardom SR2760 from Taiwan-based Raidon Technology, fits small businesses.

Engineers priced the entire setup from start to finish at $680.90. The bulk of the price tag, as expected, consists of the two drives in the RAID array. Depending on the size and make of the disk drives, the final price tag may be significantly lower or higher.

1. Getting Started: The first step is to get all the components together.

A part of Raidon's SOHORAID series, the SR2760-2S-S2 is a 3.5" drive module that can hold up to two 2.5" hard disk drives. The box configures the two drives under RAID 0 for data striping, or RAID 1 for data mirroring.

The cost of the unit: $176.60

The SR2760 requires two SATA II laptop hard drives. While it is recommended that both drives be the exact same brand and specification, it is not required. Unlike most RAID solutions, the Stardom SR2760 does not require drives to have same storage capacity or even be the same brand. This is particularly good news for businesses who buy drives on an as-needed-basis. They don't need to stock up on drives ahead of time, or replace the entire drive array every time a drive fails because the drive model no longer exists.

The SR2760 product comes with an accessory bag with some screws. It also requires a SATA-22 cable for power and a spare SATA cable to connect to the motherboard. If the motherboard doesn't have an available SATA connector, installing a SATA card into an available PCI or PCIe slot will solve that problem.

2. Pick a configuration: A little switch on the back of the module "sets" the RAID configuration to either level 0 or level 1. By default, the module comes from the factory preset to RAID 1 mode. For data striping instead of data mirroring, slide the switch to the right for RAID 0.

Data striping speeds up drive performance, but there's no fault tolerance. As far as the machine is concerned, the array is treated as a large single disk with storage roughly equal to the sum of the two drives' capacity. Multiple read/write can be operated on the drive, resulting in speeds and performance greater than that of a single disk. However, the data is scattered across the physical drives so if one of the drives fails, the entire array fails and all the data is lost. It's the price to pay for faster I/O performance.

On the other hand, RAID 1, data mirroring, puts identical data on each drive. As a result, it is much slower than a single drive because data has to be written in both places. The resulting storage capacity is equal to the smallest drive in the array. Mirroring is reliable because even when one drive fails, the other one still has all the data.

Test Center engineers chose RAID 1 and left the switch alone.

NEXT: Dealing with the drives 3. Installing the module: After opening up the machine, the drive module is mounted into an available 3.5" drive bay. Since the module is the same size as a floppy drive, it fits easily inside the drive bay and can be secured tightly inside the machine.

Connect the SATA 22 power cable to the power supply and the SATA cable to the motherboard. The SATA connectors all have notches at one end to indicate which way to position the cables.

At this point, the machine can be closed back up.

Cost of the SATA 22 power cable: $6.30

4. Installing the drives: Remove the drive trays from their slots on the module and remove the safety support bracket inside each tray. The bracket is only used to support the tray when it leaves the factory. Once the drives are mounted, they are unnecessary.

Engineeres had two 200-Gbyte Deskstar 7K200 laptop hard disk drives from Hitachi. Each drive was mounted on to the drive trays. The screws that came in the accessory bag secured the drives into the tray.

Once the drives are mounted, insert the tray into the module. The drive's SATA connectors should plug directly into the connectors inside the slot with an audible click. The tray should be all the way inside, and when the slot is locked, the drive should not be sticking out or loose.

The top drive bay is HDD0 and considered the "source" under RAID 1. As long as there is a disk drive in the top slot, the SR2760 can work with just one drive.

Once both drives have been inserted, the machine can be powered on to finish setting up the RAID array.

Cost of the disk drives: $249 each, $498 total.

5. Detecting the drives: The computer's BIOS automatically detects the two drives inside the SR2760 as a single drive. The operating system, whether it's Linux, Microsoft Windows, or Macintosh, also detects the new drive as a single storage drive. The drives can be partitioned, initialized and formatted using the native tools within the operating system.

Engineers initialized and formatted the drives using the disk management tools in Windows XP.

Blue and red LEDs next to each drive provide a visual check to each drive's health status. If there is no drive in the slot or the drive fails, the lights alternate between red and blue. Healthy drives, whether they are rebuilding, initializing or being accessed, flash purple lights.

The SR2760 supports hot-swapping under RAID 1, so the dead drive can be replaced with a new one without powering down the machine. As soon as the new drive is in place, it will be initialized and the data mirror will be rebuilt automatically.

Final thoughts: The system is up and ready to go with a fully configured hardware RAID 1 solution. Engineers had a working 200-Gbyte data mirror in less than 30 minutes.