How do you setup RAID 10 with Disk Utility?

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Level 4

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How do you setup RAID 10 with Disk Utility?

I read a post that indicated a Mac Pro user created two mirrors and then striped them with Disk Utility to create a RAID 10.

I tried this but Disk Utiity will not allow me to stripe the two mirrors. I tried dragging and using the "+" button. In each case no RAID 10 could be created.

Could someone list the exact procedure for creating a RAID 10 using Disk Utility?

Thank you

Mac Pro 2.66, Mac OS X (10.4.7)

Posted on Sep 14, 2006 7:07 AM

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Answer 1

Sep 14, 2006 7:18 AM in response to mbean

I implemented RAID 10 with my drives using Disk Utility. The trick is to be sure that your mirrored set are correct unmounted. Unless you do this you will not be able to add them to a stripe. I actually did it using Disk Utility while booted off the intallation DVD.

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Answer 2

mbean Author

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Sep 14, 2006 7:50 AM in response to infinite vortex

I dismounted the two mirror partitions by dragging them to the trash and then selected each mirror RAID icon and pushed the + button. This placed them in the working box of Disk Utility.

However, the create button is greyed out and will not work. I am using 4 drives on two 2-port SATA host adapters.

Can you please provide a detailed step by step of how you achieved RAID 10 with Disk Utility?

Thank you

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Answer 3

Sep 14, 2006 8:03 AM in response to mbean

I had the same problem trying to setup a stripe of 2 mirrors I had created in Disk Utility.

Somebody suggested I try the command line version which worked like a charm.

Just boot from the install dvd and pick terminal from the tools menu. Then 'man diskutil' to see the options. Start with 'diskutil list' to see the partition map. Then do a 'diskutil createRAID ....' (see man page for the correct parameters). You may have to unmount the disks before you can put them in the top level raid -- not sure.

Good luck!

Mac Pro 2.66 Mac OS X (10.4.7)

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Answer 4

Sep 14, 2006 8:06 AM in response to mbean

For some reason dragging drives into the trash doesn't unmount them correctly. Anyway, what I did was…

1) Boot from the Installation DVD.

2) Open Disk Utility.

3) Set the partition scheme to GUID Partition Table and partitioned all drive with 1 MacOS Extended (Journaled) partition. (I zero'd each drive after this which may not be important to you)

4) Created my RAID mirrors with drives 1 and 2 to "Mirror A" and drives 3 and 4 to "Mirror B".

5) Restarted the Mac Pro and booted from the Installation DVD again and re-entered DU.

6) Selected each "Mirror" and selected "Unmount" from the top buttons.

7) Created a new Stripe set (called "Stripe" - how original) and dragged each mirror into the set.

Maybe I had to recreate a partition but that was it.

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Answer 5

mbean Author

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Sep 14, 2006 9:18 AM in response to infinite vortex

I would like to use Disk Utility to create the RAID 10 but when I follow your exact process it does not work. What Mac OS X build do you have? Mine is 8K1079.

Thank you!

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Answer 6

mbean Author

Level 4

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Sep 14, 2006 9:29 AM in response to Steve Hoffman2

I had the same problem trying to setup a stripe of 2
mirrors I had created in Disk Utility.

Somebody suggested I try the command line version
which worked like a charm.

Just boot from the install dvd and pick terminal from
the tools menu. Then 'man diskutil' to see the
options. Start with 'diskutil list' to see the
partition map. Then do a 'diskutil createRAID ....'

Unfortunately, I suck at terminal. I looked at the "man diskutil" output but it does not tell me how to create a RAID. Is there any chance you could please provide a step by step instruction on how to use diskutil to create a RAID 10 with terminal? Hopefully without sending me commands that erase my boot drive 😉

Thank you.

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Answer 7

Sep 14, 2006 10:03 AM in response to mbean

I have Mac OS X Build 8K1124 and I believe that came with my Mac Pro as I've not required a Mac OS X update via Software Update.

Now, I have to honest, I'm not entirely sure that was the exact process. As you can appreciate I don't have another 4 drives to try this again so I'll do my best here.

It's definitely right up until the part of making the mirrors and unmounting them, that I know for sure. What I don't remeber is what I had selected to get to the RAID tab to create the Stripe Set. I believe I had one of the mirror partitions selected, that is, either "disk5" or "disk6", which brought up the RAID tab that then allowed me to create the stripe set.

I then created the set and then dragged the mirrors (I believe disk5 and disk6) into the set.

If you can't do this can you let me know how your situation deviates?

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Answer 8

mbean Author

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Sep 14, 2006 10:18 AM in response to infinite vortex

I then created the set and then dragged the mirrors
(I believe disk5 and disk6) into the set.

If you can't do this can you let me know how your
situation deviates?

I setup the two mirrors and dismount them using the DU dismount button. Then I select one Mirror and touch on the RAID tab. DU will not allow me to drag and drop either mirror into the box but the "+" function will work. However, once I get the mirrors in the DU box with the "+" function the button that creates the RAID is greyed out.

My best guess here is that the system version you have is more advanced in this respect. Otherwise we should of had the same results. I am guessing that the Mac Pros shipping from China to retailers have the old 10.4.7 version while those that came from the Apple store have the new 10.4.7 build. Did you buy your Mac Pro from Apple?

I may have to wait a few days for 10.4.8 unless I can get a step by step for diskutil.

Thank you.

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Answer 9

Sep 14, 2006 10:35 AM in response to mbean

Be careful as I remember there was a little trick to it. What you needed to do was in actual fact create the Stripe with no drives and then add the drives. I remember having to drag the mirrored sets into a stripe that was already created. Unfortunately I wasn't paying 100% attention to the process and everything seemed to look right so I just went with it.

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Answer 10

mbean Author

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Sep 14, 2006 10:51 AM in response to infinite vortex

Disk Utility does NOT allow you to create a RAID with no drives in it. The create button is greyed out in that situation.

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Answer 11

Sep 14, 2006 11:14 AM in response to mbean

Then I'm at a loss as to what I did exactly. I do distinctly recall the process of creating the the stripe from the mirrors didn't completely make sense but what that was exactly I have no idea.

I am sorry.

Maybe it is a difference in Disk Utility as you thought. If you want give me an e-mail address I can e-mail you my DU (which is version 10.5.8). 🙂

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Answer 12

mbean Author

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Sep 14, 2006 11:26 AM in response to infinite vortex

Please send a zipped Disk Utility to amugweb@mac.com and we will see if that makes a difference.

Thank you

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Answer 13

The hatter

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Sep 14, 2006 11:29 AM in response to mbean

I was looking on the Apple XRAID page and that talks about first creating two mirrors, then stripping the mirrors as a supported configuration.

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Answer 14

mbean Author

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Sep 14, 2006 11:52 AM in response to The hatter

I was looking on the Apple XRAID page and that talks
about first creating two mirrors, then stripping the
mirrors as a supported configuration.

Let me know if you are successful at doing it 😉

The iTunes 7 download said it was an improvement too. I did not know that it would not read all of the cover art I had put in there over the years or that it would distort my iTunes listings and add duplicates. What a pain. Sometimes you need a show me instead of a read me 😉

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Answer 15

The hatter

Level 9

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Sep 14, 2006 11:53 AM in response to mbean

Sure... soon as someone can send 4 x 160GB WD RE drives ;-))

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