How do you setup RAID 10 with Disk Utility?

I downloaded your DU and it is a newer version. However, it was unable to create a RAID 10 disk array. The mirrors are easily created but the stripe of them is a no go.

I could not get the Disk Utility application to create a RAID 10 but I was able to figure out diskutil to get it to work to create a RAID 10. Here are the steps that I used for those interested.

1. Open Terminal. Use the command "diskutil list".

2. Look for the name of the disk with a * next to it and make sure that the real disk name is listed in the "type name". Write down the "disk number" names of the volumes you want to work with.

3. Use the following diskutil command to create the mirrors.
"diskutil createRAID mirror RAID10 HFS+ disk4 disk6"
Replace disk4 disk6 with your disk numbers that you discovered in step 2 above. This command will create each mrror. Create two mirror sets.

4. As each mirror is created write down the disk number that is reported in this line: "Creating file system on RAID volume "disk5 "

5. Use the numbers of the mirror disks, as discovered in step 4 to create the stripe of the two mirrors. Use the command:
"diskutil createRAID stripe RAID10 HFS+ disk1 disk5"
Substitute disk1 disk5 in the line above with the disk numbers discovered in step 4 above.

Your RAID 10 is now completed.

If someone else knows of a better way feel free to post it here.

I am glad the RAID 1/0 instructions worked for you.

I am glad the RAID 1/0 instructions worked for you.

If a drive fails in the RAID 1/0 setup you can rebuild it with diskutil.

Drive Failure Procedure
First you determine which mirror failed by looking at it with Disk Utility. Next, use the command:
"diskutil repairMirror raidDisk newDisk"

raidDisk is replaced with the disk number of the failed mirror not the RAID 1/0 number. newDisk is simply the number of the newly inserted replacement hard drive.

The failed drive will be replaced and begin to rebuild the RAID 1/0. It takes approximately two hours for the mirror to rebuild using 300GB hard drives and the RAID 1/0 is still available for use during this process. A progress bar is displayed in Disk Utility that shows the progress of the rebuild even when diskutil was actually the initiator of the rebuild. Clicking on the progress bar shows the estimated time left to rebuild.

Have fun!

As I understand it, first 2 drives are
striped. Second 2 drives are striped. First stripe
and second stripe are mirrored. Is this right?

Dear fuzzydog,
To make a RAID 1/0, first you create the mirror setups. That is what the 1 indicates - RAID 1 Mirror. Then you stripe all of the the mirror volumes using RAID 0. That is why they call it RAID 1/0.

The system you are describing above is a RAID 0/1. I tried that setup and while it works, I was unable to get it to rebuild when a hard drive failure occured. While you could back it up to another set of hard drives, I wanted a RAID that would rebuild itself.

When I create a complex RAID such as RAID 1/0, RAID 0/1, RAID 5, RAID 6 or RAID 5/0 the first thing I test is the RAID sets ability to rebuild. You can do that by simply removing one of the hard drives and see if you can find a way to get the RAID to rebuild itself.

If you are successful then write the procedure down and put it somewhere where you can find it when a failure occurs. Then start using your new RAID. If you cannot find a way to rebuild your RAID then I would find another way to create the RAID until a rebuild procedure was discovered.

Have fun!