Four drives plus Mac OS X's Disk Utility will bring your Mac Pro into the 21st century.

 

WHAT YOU NEED

> Mac Pro ($2,499 and up, www.apple.com)
> Four identical hard drives (if you didn't get them BTO)

 

If the word RAID sends you screaming in terror like that big, hairy Brooklyn cockroach in the old TV ads for bug spray, it's time to get reacquainted with the concept as it applies to your Mac. When it comes to high-end storage, RAID stands for Redundant Array of Independent (or Inexpensive) Disks (or Drives), and you can use it to speed up your storage or keep a running backup of your entire system, among other tricks. Armed with Mac OS X and a Mac Pro chock-full of hard drives, we'll transform the four drives into two high-speed striped RAIDs, which we'll then roll into a mirrored RAID set to continually back up any changes to the main-system RAID volume. Hey, get back here - setting up this RAID of RAIDs is painless. The toughest part is ponying up for the iron: All flavors of RAID work best if all of the hard drives involved are identical in every way (capacity, cache, rotation speed, manufacturer...aw heck, just get four of the exact same model). However, you'll pay about $1,400 more than the base price if you order your Mac Pro from Apple preloaded with four 500GB drives. FYI: Similar drives sell for $199 each at Other World Computing (www.macsales.com).

 

---

 

Step 1: Carry the Cartridge

 

If you bought your Mac Pro with all four drive-bays occupied, bully for you - proceed to step 4. Otherwise, it's time to earn that $600 preinstalled-drive surcharge that you saved. Just remember, try to find the same model and size drive that came in your Mac, or get four new identical drives. And no bargain-basement drives, OK? Shut down and remove the Mac's AC power and any other attached cords, open the door-release latch, and pull the door open from the top. The latch also unlocks the removable drive-bay carriages, so leave the latch up as you pull out the empty carriages. Your stock hard drive should be in the bay marked number 1, nearest the Mac’s front.

 

The removable hard-drive carriers won’t budge until you unlock them.

 

---

 

Step 2: Mount Up

 

Now install your new hard drives in the drive-bay carriages, tighten the screws, and slide the carriages into their respective slots - number 1 up front, number 4 in the rear. (Yes, your Mac will self-destruct if you don't install them in numerical order. Maybe.) With all of the drive-bay carriages firmly inserted, replace the outer door and snap it into position, and then close the latch-release lever. Considering that you just added a TB or two of storage to your Mac, maybe now's a good time to use that latch-release lever’s lock slot.

 

Make sure you get the connectors facing in, toward their respective connections.

 

---

 

Step 3: Don’t Forget Your Data

 

If you've been using your Mac Pro for a while, you've probably got some data on it - so get it now or kiss it good-bye. Setting up any kind of RAID requires erasing and reformatting all of the drives. You could clone your existing system and restore it onto the RAID volume, but as long as you're going to all this trouble, we suggest moving all of your data (iTunes songs and videos, photos, iMovie projects, and any important documents) to an external hard drive and - after finishing this how-to - starting fresh on your RAID volume with a newly installed OS X system, and then installing your apps and restoring any files from the external drive.

 

Playing with RAID requires erasing all of the participating hard drives.

 

---

 

Step 4: Installus Interruptus

 

With all of your important files removed from the Mac Pro's original hard drive, insert the System Install disc that came with your Mac. Double-click the Install icon and follow the prompts, or simply restart your Mac and hold the C key to reboot from the disc. Once the menubar appears, select Utilities > Disk Utility and roll up your sleeves - it’s time to RAID.

 

Patience, Grasshopper. Starting from the Mac OS X Install disc is s-l-o-w.

 

---

 

Step 5: Stripes All Around

 

Select one of the drives from Disk Utility's left-side pane and click the RAID tab. Give the impending RAID volume a name (we called ours Ham), leave the volume format at the default Mac OS Extended (Journaled), and select Striped RAID Set from the Raid Type pull-down menu. Now drag in the drives that you want to use from the left-side pane. Once both drives are added to the RAID set in Disk Utility's main panel, click on one and make sure the RAID Type pull-down says Slice. Then do the same for the other drive in the set.

 

Make sure both drives are set to Slice.

 

---

 

Step 6: Exercise Your Options

 

Disk Utility provides just one configuration option for a striped RAID set - but it's a good one, so click Options. Use the Block Size pull-down menu to determine how the RAID set will distribute your data - remember, each drive receives "stripes" of data that are actually a series of data blocks. If your RAID will be used primarily for large-file projects such as audio or video, select the maximum block size (256KB); conversely, if you're doing something fun like hosting a database full of small chunks of data, pick a smaller block size. Click OK.

 

Pick a block size that fits your needs.

 

---

 

Step 7: Double Up

 

Mac OS X's Disk Utility handles all of the RAID magic for you - just click Create. After about a minute, your first striped set will be ready. Now click the plus-sign icon and repeat the process to create another striped RAID set on the other two drives, with the same Options configuration as the first, and then click Create. Notice in the screenshot how we named the drives Disk1, Disk2, and so on—that makes wrangling them into dual RAIDs a little less confusing. (Notice also that we configured the RAID from another Mac, with the Mac Pro mounted in FireWire Target Disk Mode—otherwise we wouldn't have been able to capture these screenshots.)

 

It may be easy to miss the fact that the RAIDed drives are grayed out and not selectable, but they are.

 

---

 

Step 8: Mirror, Mirror

 

Disk Utility will show you two volumes under the four hard drives in the Volumes list. Click one (select the RAID tab if you're not already there) and give the new volume a name. Keep the Volume Format as Mac OS Extended (Journaled) and change the RAID Type pull-down to Mirrored RAID. Wondering about that RAID Mirror AutoRebuild setting (Options) from step 6? You can ignore it unless you're using removable drives for your RAID, in which case Disk Utility can automatically RAID up whenever you attach them. Click Create.

 

Now set one of the striped volumes to mirror the other—presto! Speed and redundancy!

 

---

 

Step 9: Fill ’Er Up and Hang On!

 

Once your mirrored set of striped RAID sets is complete, quit Disk Utility and install Mac OS X. Your Mac now looks like it's got one 1TB drive (actually 930GB), not the four 500GB drives that you know are in there. That's the cost of keeping a live backup: You pay for it with half of your storage space. But when a drive fails, your Mac will automatically recover any lost data from the backup - and walk you through the process of replacing the failed drive with a new one.

 

Your expensive 2TB of drives just became 1TB—that’s the price of redundancy.