To RAID or Not to RAID?
Personal RAID storage is a hot topic—even somewhat controversial. Theoretically RAID 0 offers better performance, but at the cost of increased risk: If one of the two drives fails, you lose your data. RAID 1 offers redundancy and protection, but you only get half the capacity of the two combined drives.
What if you could do both, with just a single pair of drives? As it turns out, you can, if your motherboard is based on Intels 900 series chipset. The RAID-enabled version of Intels latest I/O controller hub, ICH6R, lets you use two drives to set up both a RAID 0 array and a RAID 1 array.
This makes a lot of sense. Serial ATA drive capacities are at 300GB and more. Unless youre editing massive video files, a 600GB RAID 0 array makes little sense. And tying up two 300GB drives to get a sin-gle, 300GB RAID 1 array may be overkill for most users. On the other hand, many users are editing digital photographs and creating DVDs from DV camcorder content, which makes RAID 0 useful, but they can also appreciate the security of RAID 1s redundancy.
Well show you how to create a mixed RAID array setup from two drives. Well also suggest strategies for boot drives and sizing the array. But first, lets move on to the nuts and bolts of setup.
Which Configuration is Best
?”> Matrix RAID is available on any motherboard or system with the ICH6R I/O controller hub—its not restricted to Intel motherboards. However, well use Intels latest 925XE motherboard, the D925XECV2. We need to zero in on the RAID BIOS, which will be the same on any motherboard using ICH6R, including Taiwanese boards.
Before we launch into the intricacies of the BIOS, you need to decide how you want to configure your RAID drives. Intels Matrix RAID feature lets you create two RAID volumes using one pair of drives. As-suming you want to create more than one RAID volume, here are your options:
- Two drives in a RAID 0 array
- Two drives in a RAID 1 array
- One RAID 1 and one RAID 0, RAID 0 drive bootable
- One RAID 0 and one RAID 1, RAID 1 drive bootable
If youre just looking for raw performance, then using two RAID 0 drives is probably pointless. Just create one RAID 0 volume. You get no protection from having two drives in a RAID 0 array if one of the drives fails. If youre really a belt-and-suspenders kind of person, then two RAID 1 volumes may make some sense. Unless you simply dislike having large volumes, it may be better just creating one large volume.
The most intriguing configuration results when you create one RAID 0 and one RAID 1 volume. That way, youll have a RAID 1 volume to protect valuable data and a RAID 0 volume for performance. If you decide on this course, the next question is which drive you should make bootable.
This is a critical point for Windows users, because Windows will only install on the first RAID volume created in the RAID BIOS. So if you want to boot from RAID 0, to benefit from faster boot and load times, then youll want to install Windows on the RAID 0 drive. If you want the bootable drive to be the safer one, then youll want RAID 1 to be the boot drive. That way, if one drive dies, youll still be able to boot into Windows. But you will lose anything on the RAID 0 volume.
The first RAID volume created usually uses the outer tracks of the hard drive. That means if you use the RAID 1 volume as the boot drive, then the RAID 0 array be built using the slower, inner tracks. Of course, you could simply set up a small RAID 0 array to be the boot drive, and use the RAID 1 volume as your data drive. It all depends on what youre trying to accomplish. If all you want is a fast volume for Photoshop scratch files, editing DV capture files, or Windows swap files, then creating the RAID 0 array second will still net some performance gain.
Now that weve visited configuration issues, lets roll up our sleeves and create a pair of arrays.
Begin with the BIOS
To create Matrix RAID volumes, youll need an Intel-based system with ICH6R and two Serial ATA drives. Its generally best to use two identical drives. Although you can use drives of different sizes or even brands, that would likely waste some space. Setting up a pair of Matrix RAID drives involves three primary steps, assuming that the hardware is already in place:
- Go into the system BIOS setup and configure the SATA ports for RAID.
- Use the RAID BIOS screen (different from BIOS setup) to configure the drives.
- Once the arrays are created, return to BIOS setup to ensure correct boot order.
Initial BIOS Setup Chores
The first thing to do is to ensure that the SATA drive ports are configured for RAID support.
Some BIOS setup screens also may enable or disable the RAID BIOS, even if RAID support is turned on. Make sure the RAID BIOS is enabled.
Once thats done, its time to configure the arrays in the RAID BIOS.
Creating the First Array
Now lets turn to the RAID BIOS. Usually, youll be asked to press CTRL-I to enter the RAID BIOS on sys-tems using Intel chipsets. Were assuming here that the RAID 0 volume is to be the first array, with Windows to be installed on it. But if you want RAID 1 to be the first volume, just reverse the steps. Note that some BIOS screen shots may show a third physical drive. Well ignore that for our purposes here.
All drives start as non-RAID drives. Using the cursor and Enter keys, select “Create RAID Volume” to enter the creation screen.
The default 128KB stripe size is fine for most desktop applications. If youre running databases with small data items, you may want a smaller stripe size.
All navigation uses the cursor keys, space bar, and Enter keys. You select the drives by pressing the space bar, then moving down the list with the cursor key to the next drive.
Were using a pair of 74GB, Western Digital Raptor drives in our array. So lets size our RAID 0 volume to 70GB, which is about half the maximum.
Now lets move on to the second array.
Building the Second Array
Once weve created the first array, well be returned to the main RAID BIOS screen.
Select “Create RAID Volume” again.
We skip past the sizing step, as the RAID BIOS only lets us create two arrays with two drives. The sec-ond array is automatically sized to fill the remaining space.
Installing Windows and the
RAID Driver”>One of the curious quirks of Windows XP is that you need a floppy disk drive to install drivers for custom disk controllers. Weve never tried USB keys or USB floppies for this chore, but we do know that Windows Setup will stubbornly refuse to search a CD-ROM drive for this purpose.
So youll need whats commonly called the “F6 floppy”. Thats because you press the F6 key on your keyboard when Windows setup launches. Youll see a question on the bottom of the screen telling you to “Press F6 if you need to install a third party SCSI or RAID driver”. Press F6 at this point.
Eventually, youll see a screen asking for the driver.
When you press the S key at the screen, Windows setup will search the F6 floppy and find the driver.
Choose the 82801FR SATA RAID Controller driver with the cursor keys and hit the Enter key.
Make sure youve selected the correct driver. Once you commit, you cant change, and the result will be a blue screen crash on the first boot after Windows is installed—and youll get to start over.
Note that the current drivers for Intels RAID may not be digitally signed or otherwise approved by Mi-crosoft, so youll need to ignore the warnings from Windows Setup and make sure you press the “Yes” button. This will likely happen twice, once with no hint as to which file is causing Windows to freak out.
Finally, we can format the primary partition and install Windows. Note that if you select the second drive and attempt to use it as the boot drive, Windows Setup will simply tell you that this drive is not usable.
From this point on, Windows installs normally. You can, if you like, install the Intel Application Accelerator, a caching driver for Intels RAID arrays, but its not necessary. Once Windows is installed and running, you can use the standard Windows tools to partition and format the unpartitioned second array. Just use the Run command and type
Now youve got a system with two RAID arrays created from a pair of drives. Just make sure to keep the most valuable data on the RAID 1 array. That way, if one drive does go South, the data on that drive is still recoverable.
With the prices of drives plummeting, RAID arrays make more sense, particularly RAID 1 arrays. As we collect more valuable digital “stuff”—pictures, music, home movies, documents—RAID 1 be-comes an increasingly useful option. In the long run, it may be more useful in the real world than RAID 0.