RAID 1 setup on Main MacBook Pro Hard Drive Behavior!

Question

Level 1

5 points

RAID 1 setup on Main MacBook Pro Hard Drive Behavior!

Hello...

I have:

-MacBookPro - OS X 10.6.4 - with 1-TB 2.5" Hard Drive.
-A 1-TB 3.5" External USB Drive.
-Master Hard Drive booting and working fine.
-USB Hard Drive is attached and formatted with no problems.

My intention:

-I have the will to use RAID-1 as a solution to mirror the master Hard Drive (the only Hard Drive in any Mac Book Pro!) to the 1-TB USB Hard Drive.
-I read that I can do that using the MacBook Pro Recovery CD. This is with using the RAID tab in the Disk Utility.(No problem so far).

Question/Doubt:

-It is a Laptop Computer, and I take it with me everywhere; normally, I would disconnect the computer from the USB hard drive when I am on the move.
-I would use the computer at work or anywhere else; so, data would be accessed, modified, added, or even deleted!
-Now, if I connect the computer back to the USB Hard Drive, what will happen?
-How would the two RAID-ed hard drives behave?
-Would the Laptop recognize the Laptop Hard Drive as a master/source and the USB Hard Drive as the destination?
-How would the RAID-1 setup treat "rebuilding" for the two drives?
-What would be copied to the Destination drive? all data? changes?
-Lastly, remarks and suggestions are appreciated.

Thank you...

Ahmad

MacBook Pro 15", Mac OS X (10.6.4), MacBookPro5,4 - 2.53 GHx Intel Core 2 Duo - 4 GB 1067 MHz DDR3

Posted on Sep 1, 2010 7:23 PM

Reply

Answer 1

Kappy

Level 10

361,741 points

Sep 1, 2010 7:57 PM in response to AhmadMarafi

What you want to do is not best done the way you describe. All you need to do is backup the MBP's hard drive to your external drive using Time Machine or any other backup utility. You are looking for a backup solution for one drive to another single drive. This is not a solution for which RAIDs are intended nor work well.

I think you may need to take a little time to become more familiar with backup and restore procedures and design.

I backup all my laptops to external drives using a backup utility that automatically runs as soon as the backup drive is connected. I think this is what you should be doing for the situation you have described and forget RAIDs.

Reply

Answer 2

AhmadMarafi Author

Level 1

5 points

Sep 2, 2010 6:24 AM in response to AhmadMarafi

Hello,

Thank you for the answer.
I am familiar with the method you described.

Let me revise the question:

Since the option is available in OS X and we can RAID-1 the internal(Master Bootable) drive with an external one, and I assume that the laptop is always attached to the computer from booting until shutting down the computer....

Now, if the external drive's cable accidentally gets disconnected and I boot up the laptop without the second hard-drive being attached to the laptop.

-What would happen?
-Would the Laptop boot normally?
-If I link the USB Drive again, should I rebuild the RAID-1 chain again using Disk Utility after booting from the recovery CD?

This would answer my question clearly.

Thank you,,,

Ahmad

Reply

Answer 3

Kappy

Level 10

361,741 points

Sep 2, 2010 10:07 AM in response to AhmadMarafi

Were that to happen the RAID would be broken. In theory the computer should boot from the internal drive unless it is corrupted by the accidental disconnect. But the entire scenario requires that the external drive always be connected meaning you cannot be mobile without the external drive.

Again, what you want to do is simply a bad idea. The external drive should simply be used as a backup drive. There is no benefit from using it as part of a mirrored RAID.

Oh, and yes you would need to rebuild the RAID risking loss or damage to data in the process.

Reply

Answer 4

WillieF

Level 1

0 points

Sep 5, 2010 12:54 PM in response to AhmadMarafi

I understand what you want to do. You want a raid 1 so you don't have to keep running backups. That is understood. But, disconnecting one drive will not work. What you should do, is get rid of your superdrive and install an identical 1TB drive in its place, then run both internal drives as a raid 1. Then your problem is solved. You will have a permanent backup of everything you do, as you do it on your laptop no matter where you are.

Another solution you could use is have only your system software and programs on your internal hard drive then use an external raid for all of your important stuff. But you will not be able to access your files on the go unless you copy them to your laptops internal drive, Then any changes to files while you are out will not be protected until you hook back up at home.

Reply

Answer 5

prosco50

Level 1

4 points

Sep 13, 2010 6:37 AM in response to AhmadMarafi

It seems that sometimes we try to influence questioners into another solution that they have not requested.

It seems that Ahmed is convinced that he wants a raid system so that he can swap to the other drive if a problem arises. He doesn't want to have to wait until he re-fits a new drive but that he can continue working with the raid.

My advice would be that you must always have your external raid drive with you so that every time you run your machine, your raid should also be connected. These drives can be extremely small and you should have little problem in carrying it with you.

There are plenty of suggestions on how to set this up with an external USB drive

Reply

Answer 6

Kappy

Level 10

361,741 points

Sep 13, 2010 10:13 AM in response to prosco50

Sometimes we try to influence them into a better solution even though it's not what was requested. Helping a poster do the wrong thing is not what most of us are here to do. If that's what you're here to do, then I highly recommend reconsidering what you are doing.

Reply