Rebuilding a Mirrored Raid using Disk Utility

I have a mirrored raid set up via disk utility. For some reason one drive was switched off recently so the 2 drives are now out of sync. Disk utility now says the raid is 'Degraded' with one of the slices marked as 'failed'
I can ignore this as the drive appears fine on the desktop. But I need it to be working correctly as a fully operating RAID.
If I click 'rebuild' it gives a warning saying 'Rebuilding a RAID set will destroy all information on the replacement disk “RAID Slice”.
SO- I'm assuming rebuild will correct the error and make it work but I'm concerned about this warning about destroying data! I assume it will simply copy everything from Drive A to the 'degraded' Drive B??
Thanks for any suggestions.

"SO- I'm assuming rebuild will correct the error and make it work but I'm concerned about this warning about destroying data! I assume it will simply copy everything from Drive A to the 'degraded' Drive B??"
This should indeed be the way it goes but since i do not have enough experience with that kind or RAID setup i strongly suggest backing up / cloning drive A to an external before doing the rebuild... just in case.

Similar Messages

"Create" button dim when attempting to setup mirrored RAID in Disk Utility.

I'm trying to setup a mirrored RAID in Disk Utility (v10.5.6) in MacOS 10.4.11 on a PowerMac G5. I've got the System and all of my files on a 500 GB Seagate internal drive and I've added a blank 500 GB Western Digital internal drive to be the mirror. When I boot from the Seagate drive and run Disk Utility, I can follow all of the instructions for setting up a mirrored RAID (except the last instruction):
1) Launch disk utility.
2) Select my boot drive.
3) Click on the RAID tab.
4) Enter a RAID Set Name and select a Volume Format (Mac OS Extended Journaled).
5) Drag a drive or volume to the set. Okay, I actually have a problem here, because if I drag the boot volume or drive to the set, nothing happens (it doesn't appear in the selection box). So I drag the blank volume to the set and it shows up in the selection box.
6) Select RAID type (RAID Slice).
7) Click the "Create" button.
That's the step that I can't complete; the "Create" button is dimmed (grayed out, disabled). My boot drive isn't partitioned (it has just one volume), I've run Disk Utility to repair Disk Permissions before I attempted to set up the RAID, and both drives are formatted as "Mac OS Extended Journaled." The only potential cause I can think of is that the two drives I'm using, though they're both 500 GB drives, are from different manufacturers. I can't imagine that would make a difference though.
Why is the "Create" button dimmed?
Any help would be GREATLY appreciated!
Thanks,
Scott

Hi there,
Thanks for your help!
Your explanation makes sense. I've just recovered from a hard drive failure and although I'd backed up most of the files the night before, I still lost a day's worth of email and several days worth of other files. Mirroring appealed to me because then I'd always have a completely up-to-date copy of everything, but your bad experiences with it give me pause.
Is there another backup strategy you can recommend that would give me really up-to-date backups of my entire boot volume?
Thanks again!
Scott

Setting up XServe mirrored drives using disk utility

We are getting ready to format a server and reload the OS. We currently have 4 drives (250gb) each. I want to know the best way to set the drives up so they will be redundant. Do I include the first drive, which will contain the server software? This is an older G4 XServe box with 2gb of memory. I do not have a RAID card in this server. This will be software RAID.
Any suggestions would be greatly appreciated.
Scot

Depending on how much redundancy you're looking for you can do it a number of ways, but here are the basics.
1) Boot from your installation media
2) After you choose a language you can invoke the Disk Utility
3) Use DU to wipe the disk and create a RAID 1 - add desired disks to the RAID*
4) Once the RAID is finished it will appear as a single drive
5) Quit Disk Utility and return to the Installation process and install the OS on the "Disk" which is actually the new RAID.
The set-up you want dictates the "desired disks" in step 3 above. Usually people create one mirror of the system disk so they have a disk to boot from if the primary drive fails. If the main system disk fails you simply pop out the bad drive and reboot off the mirror. You could do more than that but it really is overkill. If you really want more protection use the other disks for making back-ups so you can rollback or find accidently deleted files rather than more copies of the same disk.
Hope that helps,
=Tod

RAID using disk utility and unequall drives

I just recieved 2 drives I need to RAID and unfortunately the retailer sent me 2 different drives.
I ordered 2 Maxtor Diamond Max10 250GB IDE drives.
I recieved one 250GB and one 300GB accidentally.
question is: Can I RAID them together anyway? (stripe, not mirror)
Will there be any disadvantages. I am using these for video editing.
Drive model numbers are as follows:
250GB drive: Maxtor 6B250R0
300GB drive: Maxtor 6B300R0
thanks a million!

Yes. You can RAID the 2 differently sized drives. No known disadvantages except for the fact that the retailer did not screw up twice and send you 2 of the 300s!
Beavis2084

Builidng RAID on mac pro using disk-utility

Hello,
i want to build a RAID on my Intel mac.
First idea was using Disk Utility (DU).
Is DU able to create RAID 5 or only RAID 0/1 ?
If yes, and hints / or useful links ?
I have googled for a while but most hints are regarding raid 0/1 and/or mac xserve systems with specific cards/controllers
or should i use: softRAId app ?
and:
if there is a solution:
is the software raid 5 at apple really too slow to be happy ? is hardware-raid the only working solution ?
best regards
fidel

Check out some of the PCIe hardware controllers. There is CalDigit
RocketRAID reviewed by AMUG (they do excellent in-depth reviews).
Areca ARC-1220 RAID might be an option at some point. Would be nice if it did - but I don't see Mac Pro or OS X support.
http://www.areca.com.tw/products/html/pcie-sata.htm
I prefer SoftRAID, but you'll have to wait for 3.6, or do as some and use Apple's and create RAID 1+0. Or XRAID

Creating RAID doesn't work using Disk Utility

When I try to create a RAID in Disk Utility, the pair gets corrupted and I get an error - "couldn't find RAID".
What is missing? Is there something else to install?
I'm trying this on an external USB drive.

I gave up.

RAID with Disk Utility question

I've setup a RAID array in disk utility for an external SATA NAS that I have. The Silicon Image Si3132 drivers are not working for Snow Leopard (the SATARAID 5 drivers) so I've installed the base non-raid drivers for 10.6.
I'm using Disk Utility to setup the RAID for now until I get updated drivers from SI. Here's my question:
Let's just say that my Mac Pro one day decides to die and I have to rebuild a new OS on the machine. I will then have this external drive where I've configured a software RAID with Mac OS X. Will I be able to rebuild this RAID and recover the data, or will I lose all of the data if the Mac needs to be rebuilt?
The external enclosure has its own controller, but these silicon image drivers do not seem to want to work as they are kernel panicking.
Will I be able to recover the RAID config with disk utility if I rebuild the machine? My thinking is NO

You have four internal hard drives; ability to boot from FW or USB, and I would include TimeMachine and clone (Carbon Copy Cloner or SuperDuper). Some WHS NAS servers also support TimeMachine and SuperDuper, but I would have local backups. Two minimum.
I would not rely on SI or RAID.
And all you need to boot from, and I'd have at least two, is a basic 30GB partition for Mac OS: a working copy of your system as is, a copy of last version installed also, AND, one "emergency" boot partition for disk maintenance and repairs.
Then use NAS as second line of backup for your data, disk images, etc.

Using Disk Utility for backup - target drive must be same size as source?

Hello. I have a 250 GB data drive that I need to back up to an external drive using Disk Utility (restore) so that I can create a RAID-1 set using the 250GB drive. The files take up only 100 GB on the drive.
Does the target external drive need to be 250 GB or just 100+ GB in size for the Disk Utility to work?
Thanks
David

I you want to make a non mirrored drive into a mirrored one you can do that with diskutil. Copying it first is not needed.
man diskutil:
enableRAID mirror|concat device
Convert single filesystem disk or volume into a unpaired mir-
ror RAID set or concat set. Ownership of the affected disk is
required.
repairMirror raidDisk newDisk
Repair a failed mirror. Supply the existing RAID as the raid-
Disk parameter. Supply the new disk as the last parameter of
the request. newDisk and raidDisk are only Device Nodes or
Disk Identifiers. Ownership of the affected disk is required.
The second disk in the mirror set needs to be as big or bigger as the first disk.
Do this booted from another disk or DVD.

Xserve RAID won't RAID in disk utility

I have a XServe RAID that won't RAID in disk utility. The XServe is fully populated and there are two arrays created. Both of those arrays show up in disk utility and will only be partitioned with an Apple Partition Map. If I try to partition them GUID, that partition fails (system formatter failed). Once, I partition them APM, two volumes show up on the desktop. Then, I try to create a software RAID with those two volumes and I can not get the volumes to RAID together. The error message in disk utility says (RAID can not be modified). I have checked the system log and it says something about a socket error or that it can not bind. Does anyone have any ideas on why I can not create this RAID?
My end goal is to have 2 hardware RAID 5's and put a striped RAID set on top of that to have one large volume for Final Cut video editing.
I'm using a Mac Pro with Atto Celerity 42ES fibre card.
Thanks

This may be a little too late, but maybe it will help. I'm not sure why this happens. I reinstalled my server, and I could not access the drives, even though they showed up in disk utility (as a blank file).
Here is what I did to fix it:
1. Open up Disk Utility
2. Make a disk image of the drive you want to mount, save this somewhere accessible (i saved it on another one of my RAID drives)
3. Erase the disk, it should then mount and be accessible
4. Restore the image onto the drive.
Cheers!

Adding Drive to Concatenated RAID in Disk Utility

Hello,
I'm having a spot of trouble with Disk Utility. 24 hours ago I added a new drive to a Concatenated Raid through Disk Utility, and clicked Update to set the process going.
Now it's not responding. It just claims to be updating. I struggle to believe that it takes this long though!
I didn't format the disk before adding it to the RAID. Is this what's causing the upset?
When I try to cancel it tells me I risk losing data on the disk. I'm not sure if it means the new disk or all disks on the array - which is a terrifying prospect. If I quit Disk Utility, will my existing data on the array be safe?
Thanks in advance for the help,
Ben

The drives are in Sonnet P500 enclosures and connected to the MacPro via a Sonnet SATA card.
On purhcase I was told this could be done, as it's a Concatenated JBOD setup. For a better description of what I mean by that, this wiki article describes it well http://en.wikipedia.org/wiki/StandardRAIDlevels.
Does this provide any further clues?
Currently there are 7x 1TB drives in 2 enclosures. I've now added 2 more 1TB drives. I can currently see and continue to use the data on the existing 7 drives. My worry though is that if I quit the disk utility I may lose the data on the 7 original drives.

Backup / Restore using Disk Utility

Hello,
I have a G4 Quicksilver 2002 with two internal hard rives: one cofigured for Mac OS X 10.4 and the other (my main) configured for Mac OS X 10.5.
I've created a backup image of the 10.4 HD using Disk Utility which is stored on an external USB drive.
My question is this - if I need to restore the 10.4 HD from the backup image, will it be bootable? The directory for the 10.4 HD appears to be corrupted, and I'll likely need to reformat the drive and attempt a restore from the archived image.
I would like to avoid the hassle of rebuilding the 10.4.11 system from scratch.
--Bill

Hi Bill,
In theory that should work.

Partitioning a disk using disk utility

I bought a rather large capacity external hard drive for use as a Time Machine backup drive along with MacOS 10.5, and figured I'd partition off 100GB of it for use as a bootable partition. So, I looked up how to partition a drive in Disk Utility, and it said:
"*To partition a startup disk:*
1) If you’re partitioning an external hard disk, make sure it’s connected to your computer. If you’re partitioning the disk you are now using as a startup disk, you must start up using another disk such as your Mac OS X install disc.
2) Open Disk Utility. If you’re in the Mac OS X Installer, choose Utilities > Disk Utility. Otherwise, double-click Disk Utility, located in the Utilities folder in your Applications folder.
3) Select the disk in the list that you want to partition, and click Partition.
4) Choose the number of partitions from the Volume Scheme pop-up menu.
5) If you can’t choose the number of partitions, you may be trying to partition your startup disk. Start up your computer with another disk, such as your Mac OS X install disc."
The external hard drive showed up in the side bar, but there was nothing in the disk utility window called "Partition" for me to click on. Nothing called "partition" existed in the menus either. I tried to customize the toolbar, thinking that "Partition" might be a button not currently on the tool bar, but I found nothing.
(I would attach screenshots of both the help window and Disk Utility, but I can't do that here.)
How do I partition a disk using Disk Utility?
Message was edited by: Berkana

3) *Select the disk* in the list that you want to partition, and click Partition.
When you select a disk that DU can partition, that is, not the volume currently booted from,
you can see the five buttons
First Aid | Erase | Partition | RAID | Restore
Also:
Don't forget to choose the "Mac OS Extended (Journaled)" formatting option.

The difference between a .dmg file & a .cdr file (using Disk Utility) ?

Hi,
In particular, I created both from a DVD using Disk Utility.
When I chose "read only" a .dmg was created.
When I chose "DVD/CD Master" a .cdr was created.
They are exactly the same size.
Is there any difference ?
Thanks in advance.
Pat De Marco

HI Pat,
From Wikipedia: A file with the extension .dmg (an abbreviation for disk image) uses a disk image format commonly found on Mac OS X. The format allows secure password protection as well as file compression and hence serves both security and file distribution functions. Its most common function is the distribution of software over the Internet. When opened, DMG files are "mounted" as a drive within the Finder.
From: Wikipedia .cdr and ISO
ISO image
Filename extension .iso
Uniform Type Identifier public.iso-image
Type of format Disk image
Standard(s) ISO 9660
An ISO image is an archive file (a.k.a. disk image) of an optical disc using a conventional ISO (International Organization for Standardization) format that is supported by many software vendors. ISO image files typically have a file extension of .ISO but Mac OS X ISO images often have the extension .CDR. The name "ISO" is taken from the ISO 9660 file system used with CD-ROM media, but an ISO image can also contain UDF file system because UDF is backward-compatible to ISO 9660.
Carolyn
Message was edited by: Carolyn Samit

How do you use disk utility to burn a bootable .iso dvd?

Anybody have a clue on how you use disk utility to burn a .iso bootable dvd disk?
I'm trying to install windows 7 rc into virtual box in OS X 10.5.7 and cannot figure out how to do this. I've already installed the windows 7 beta in virtual box and was able to make a bootable dvd disk with the .iso file on it but have no clue how I did this.
I've been searching the web but most tips are for older version of OS X.
Thanks to anybody who answers.

It's so easy, You can just burn an .iso file using DVD Creator Std instead of Disk Utility, only 3 steps to finish bur ning your .iso files:
http://www.imediacreator.com/mac-dvd-creator-standard.html#131

HT1553 Does using Disk Utility also backup MSOffice 2008 (Mac) software already installed on my Macbook Pro with Snow Leopard? If not, how would I do that?

Hi,
I'm looking to upgrade from Snow Leapord (10.6.8) to the new Mountain Lion. Have a lot of applications and softwares that I would like to back up when installing the new OS, such as MS Office, Adobe Photoshop and Illustrator. Any ideas on what is the best way to do that.
I'm not too tech savvy, so a simple solution would be appreciated.
Thanks,
Shyam

If your not very tech savvy, I would have someone assist you in the upgrade process as your about to inflict major change on your life and computer.
There are some things to consider before you upgrade.
1: The age of your machine:
My advice has been if your Mac is less than two years old and has a dedicated graphics (not all only Intel HD 3000 or 4000 CPU graphics like the 13" has)) then you stand a very good chance of 10.8 (or 10.7) running fine on your machine.
In either case you need to check the specifications of your machine to see if it meets Apple's requirements, and unfortunately those requirements are a bit low, resulting in a slower machine when you upgrade.
https://en.wikipedia.org/wiki/OS_X_Mountain_Lion
https://en.wikipedia.org/wiki/Mac_OS_X_Lion
(note: 10.7 is no longer being sold via the AppStore, you should upgrade to 10.8, however some machines can't, you can call Apple Sales to upgrade to 10.7)
If your machine originally came with 10.5, I would say forget it. Mac's don't last forever and laptops usually have a life of about 4 years with normal use. Desktops last longer of course and can withstand more OS X upgrades if Apple allows it.
2: The age of your software.
10.7 and 10.8 will not run PPC based software of old like 10.6 does, also upgrading to 10.8/10.7 may require expensive software upgrades that can hit you unexpected. Consult this site and your other needed software and hardware drivers/software (for printers/scanners,custom keyboards/mice etc) BEFORE you upgrade the operating system.
http://roaringapps.com/apps:table
3: Carbon Copy Cloner or SuperDuper "clone" (payware)
Your OS X boot partition to a new/reliable, blank powered external drive and use Disk Utility to Repair Permissions on both afterwards. You can hold the option key down and boot from this clone drive to use the computer like before if your OS X upgrade fails and the machine gets bricked. You can also use Disk Utility to erase the entire internal drive and reverse clone if you find out the OS X upgrade is not to your liking.
Make sure all other drives are disconnected, like TimeMachine when cloning or upgrading OS X, thus when you reboot TimeMachine doesn't self update itself, which can lock you out from going back in time to restore from.
Note: If you have Bootcamp, you can clone that with WinClone (payware) to another drive and recreate Bootcamp later and restore it.
4: Some firmware updates can possibly "BRICK" your hardware
Firmware updates progress in a forward manner and can't be downgraded, so what sometimes occurs is a software error by programmers or a hardware glitch on your machine won't 100% cooperate with the firmware update and thus your machine will fail to function. Sometimes even a interruption in the OS X upgrade or firmware update process will cause the problem. When this occurs, a trip to a Apple Repair is in order and if your machine is out of AppleCare (3 years) or the 1 years standard warranty your looking at a very expensive logicboard replacement. At this time you usually consider the cost not worth it and rather spend the money on the newer machine, especially if it's 2-3 years old. This can come as quite a shock as you expected to pay $20 for a OS X upgrade and now have to buy a whole new machine.
You can't not upgrade the operating system for security and bug fixes, however you make sure you have AppleCare that will protect you for three years if such a hardware bricking occurs. If you don't have AppleCare you might want to reconsider taking the chance upgrading the operating system and thus the firmware.
AppleCare can be purchased within one year of the original machine purchase, it gives one 3 years of care from the date of machine purchase, not from the date of AppleCare purchase.
5: Market share of OS x versions (apx)
10.4 4.5% security updates > no
10.5 15% security updates > no
10.6 52% security updates > yes
10.7 30% security updates > yes
10.8 2 million upgraded so far, just released
6: Your decision to upgrade or not
It depends upon your computer technical ability, the age of your machine, your software investment and your budget.
Can you afford to pay for professional assistance if your upgrade doesn't go as expected? Are you in AppleCare?
Can you afford to pay for upgrades to third party software?
Can you afford the downtime while your machine is being repaired?
Can you live without the "new features" newer OS versions provide?
Does your hardware even support the newer features?
You might decide the upgrade is not worth it for your older machine and decide to ease yourself into a new machine gradually. I took this approach with my 2006 MacBook Pro, buying a Early 2011 model. I then upgrade to 10.7 on the older 2006 machine and glad I did, because it got bricked. Turned out 10.7 was a pretty awful upgrade and I was out of AppleCare, however 10.8 seems to be "normal" far as OS X upgrades go, some problems but not mass bricking of machines.

Rebuilding a Mirrored Raid using Disk Utility

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