[zubro]

Hi,
I plan to have a second LaCie FW 250GB to backup my first one as it is far too dangerous not to do this kind of thing! ;o)
Is RAID the easyest system?
How would I set it up?
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[zubro]

Open Disk Utility

Open the Finder and navigate to the Applications folder, then to the Utilities subfolder. Launch the Disk Utility program by double-clicking its icon.


Open the RAID Pane

First select an entire disk (not a volume) from the left pane of the Disk Utility window. Make sure that you're choosing one of the disks you want to add to the RAID array (and thereby protect its data redundantly or speed up its access with striping), not your Mac's startup disk. Then click the RAID tab to open the RAID setup pane.


Drag Disks to the RAID Set

The left pane of the Disk Utility window lists all the available disks; drag the disks you want to use as the redundant disks in the RAID array into the white RAID set box (do not select the same disk you chose in step 2). You can rearrange the disks into priority order by dragging them in the box, or delete disks from the set by selecting them and clicking the Delete icon above the box. As you add disks to the set, the estimated usable size of the array (depending on your selected RAID scheme) is updated dynamically.


NOTE
You must have at least two disks in the RAID set to create a RAID array; neither of these disks can be your startup disk. Creating a RAID array destroys all the data on all the disks you add to the RAID list. Be absolutely sure that you know what you're doing before creating a RAID array!


Select the RAID Scheme

You can select Stripe or Mirror as the RAID scheme. Striping is a good scheme for enhancing access speed because it works by storing parts of the same file across different disks so that all the pieces can be read at once; striping also preserves all your combined usable disk space. However, striping doesn't provide redundancy. Mirroring copies the files across all the RAID volumes, so it does provide redundancy, but not the speed benefits of striping.

NOTE
Key Terms - Striping—A RAID data storage scheme in which parts of each file are stored on different disks so that they can all be read independently at the same time for increased access speed.

Mirroring—A RAID data storage scheme in which all disks in the array are identical copies of each other so that if an error occurs on one disk, the other disks can correct it.

There are "hybrid" RAID schemes that combine the benefits of both striping and mirroring; however, you must connect at least three RAID drives to your system to use this hybrid RAID scheme, and the scheme isn't supported by Disk Utility (which is, after all, designed for consumers with desktop Macs, rather than the high-availability server applications that use high-level RAID schemes). Professional data-center administrators might want to look into Xserve RAID, Apple's server-class RAID solution.


Choose a RAID Set Name and Format

Enter a descriptive name for the RAID array and choose a volume format. The Mac OS Extended (Journaled) format is the Mac OS X default and is generally the best way to go. You can select Mac OS Extended (Non-Journaled) to obtain a little more speed at the expense of reliability in the case of unexpected shutdowns.


Create the RAID Array

When everything is set up the way you want it, click the Create button. The RAID array is set up and mounted in the Finder as a single new volume, with the name you specified in step 5. You can then use this volume as you would any other disk; all the RAID striping or mirroring takes place under the hood, so you don't have to worry about it any more.

et voila!

source:
http://www.samspublishing.com/articl...&seqNum=11

[Mithras]

You deserve much praise for thinking about backup ahead of time.

Remember, a RAID will protect you from disk failure, but not from user failure ("DOH! I didn't mean to delete that!"). Both are likely to happen sooner or later.

Also, if you're paranoid, it's a bad idea to have all of your disks plugged in to your computer at the same time. What if your computer goes beserk in the middle of your backup?? -- you could lose both your main storage and your backup.

So depending how valuable your files really are to you, this you might:
1. Buy three drives.

Do one of these two plans:
Plan A.
2. Use two drives in a RAID-1 configuration (mirroring).
3. Once a day, or week, plug in Disk #3 and make a backup.
Note that this plan violates the 'beserker' principle above, but it protects you from disk failure throughout the day.

Plan B.
2. Start with Disk #1 plugged into your machine.
3. At the end of the day (or at whatever interval it would be painful to you to lose everything), plug in Disk #2, and copy Disk #1 -> Disk #2.
A differential backup program (rsyncX, psync) can make this fairly quick.
4. The next day, use Disk #2, and that night copy Disk #2 -> Disk #3.
5. On the third day, you'll copy Disk #3 -> Disk #1 and rotate around again.

This way, you avoid the 'beserker' situation. You could also just alternate between 2 drives for regular use, and occasionally back up to a third.

good luck

[C.J. Moof]

Originally posted by Mithras:
You deserve much praise for thinking about backup ahead of time.

Remember, a RAID will protect you from disk failure, but not from user failure ("DOH! I didn't mean to delete that!"). Both are likely to happen sooner or later.

True, but I've done 100 DOH! restores for every disk failure restore, at least by event count.... I suggest the periodic, frequent drive to drive duplication over RAID alone. RAID is your second line of defense, after having a 2nd copy of your data.