Concatenated Mirrored RAIDs

1) Can you take 4 equally sized (750GB in this case) hard drives, make 2 mirrored RAID arrays of 750GB each, then concatenate the two RAIDs using Apple's Disk Utility in OSX 10.4 Tiger?
2) Is this the best way to make a large 1.5TB, mirrored RAID using Disk Utility?
3) Also, if one of the drives fails, will I be able to remove it and just place another 750GB drive in it's place with no downtime? (Utilizing the RAID Mirror Autorebuild in Disk Utility)
Please help with these 3 questions. I'm supposed to set it all up 36 hours from this posting. (-;

It may help you to read this: http://en.wikipedia.org/wiki/RAID. Then read this: http://docs.info.apple.com/article.html?artnum=304377.

Similar Messages

Concatenated-mirrored drives

I apologize if this question has been answered, but I am unable to locate any helpful information regarding my situation in these forums.
I have a lot of media that I'm using with Front Row and I've come to the conlusion that I need to store it externally. I don't want to take any chances losing data, so I have the intention of setting up a mirrored raid. Yesterday I purchased two refurbished LaCie 500GB Big Disk Triple Interface hard drives (that's a mouth full).
One came with 2x250GB HDs and the other as 1x500GB HD. When looking at them in Disk Utility this is how they appear and I cannot separate the 1x500GB drive, which leads me to believe that it is indeed one hard drive and not two. Confusing, as they technically should be the same thing.
No matter, I figured out that I could do a concatenated RAID to combine the 2x250GB drives. However, I cannot figure out for the life of me how to create a mirror of this drive with the other, or the other way around.
Under the RAID tab of Disk Utility I try and add the concatenated RAID and it appears in the window with locks. When I add the second drive the "Update" button toward the bottom always remains greyed out.
More or less all I want to do is have two drives with exactly the same files on them in case one fails. I was hoping I could stack the concatenated RAID with a mirrored RAID to do this. Do I need to return my drive and try again?
24" iMac (Intel) Mac OS X (10.4.8) Dual 2.16GHz, 2GB RAM, 250GB HD & 7600 GT 256MB

I found the following comment in Disk Utility help, but it moves on without explaining how. No matter how I try to move the drives over to create a mirrored RAID from the concatenated drives and the 500GB drive, I am never successful.
"You can combine different RAID sets to combine their benefits. For example, if you have two 40 GB FireWire drives and an 80 GB internal drive, you can create a concatenated RAID set with the two FireWire drives, and then create a mirrored RAID set with the concatenated set and the internal drive."

How to recover data from failed drive that's part of mirrored raid

Hi Guys,
hope to get help from someone knowledgeable out there. I have a macpro and recently experienced a failed drive. I set up that failed drive as part of a mirrored raid, this set is not my primary drive and so my computer is stilling up and running but now am wondering how I access the data from the mirrored drive. Should the mirrored drive automatically mount on my desktop whereby I would be able to access the files? This is my first drive failure and I was under the impression having a mirror would duplicate my data and allow me to access it in situations like this. I'm a bit of novice in this area and not sure if the data is truly on the "mirror" or if there are things I need to do.
I launched disk utility and was able to see the mirrored drive and I selected "mount" drive but it would not mount; I then selected "verify" and got "unrecognizeable filesystem" Is this normal? Am I suppose do something to get access to the mirrored drive? Do I install a new drive in place of the failed drive and expect the raid to rebuild automatically whereby I then see the data?
Your help is much appreciated.

Even with a mirror, you still need a backup.
Along with Disk Utility, you still need 3rd party (TechTool Pro 5, Disk Warrior 4.1.1+).
And if you like to use RAID and esp mirror RAID, consider
http://www.softraid.com which is a step above (the pdf guide, manual you can download and they have a demo, so worth the read). SoftRAID can also import/convert an Apple RAID to its own format which has been known to recover drives and data.

How do I add a new drive to a degraded MIRRORED RAID set?

My mirrored raid said it was degraded because one of the drives had a failure.
Today I unplugged the faulty drive and inserted a new one.
So far so good.
I erased the new drive.
Then I went into disk utility and followed the instructions in the help about RAID but I cannot see how to add this new drive to the RAID.
I'm confused.
1) The data is all on the RAID (the good, original slice) so can I add a new slice?
2) how do I do it?
Many thanks

I don't recommend the Apple hardware RAID card, and it doesn't work with off the shelf drives. If you are using drives in RAID, first make sure they are RAID Edition or lacking that Enterprise. Same make/model/firmware.
If using Seagate, avoid anything prior to 7200.12 series. If WD the RE2/3 series.
Rebuilds are slow, and one reason why I recommend 3 drives, even if you lose one you are covered still.
Of course just having two backups per volume is more important and comes first; mirrors are great for live editing and recording (audio) but otherwise... I'd stick to stripe and redundant backups. Only if you need 24/7. Otherwise, forget mirror.

Recovering data from a damaged mirrored RAID

I have a puzzle I'm hoping you can help me with: I have a mirrored RAID array in a MD G4 which is not mounting (since going to Apple for replacing the logic board).
I have tried connecting both drives to a Forensic FireWire dock to no avail; they show up as "spare" and not as a "slice".
Any suggestions?
Yours truly,
-Tom
FYI - Below are the results of "diskutil checkRAID" and "diskutil list" on this G4:
#diskutil checkRAID
RAID SETS
Name: Stuff
Unique ID: 58607662-4550-11D8-84ED-000393D28706
Type: Mirror
Status: Offline
Device Node: disk4
Apple RAID Version: 1
# Device Node UUID Status
1 disk1s4 AF8C5D0C-24F3-4EA3-A123-5F5E22FA6D65 Spare
0 disk2s3 027E86C9-88CE-4973-9984-C7A010C422FF Spare
2 Unknown Missing/Damaged
2 Unknown Missing/Damaged
#diskutil list
/dev/disk0
#: type name size identifier
0: Applepartitionscheme *114.5 GB disk0
1: Applepartitionmap 31.5 KB disk0s1
2: Apple_HFS Backup 114.5 GB disk0s2
/dev/disk1
#: type name size identifier
0: Applepartitionscheme *149.1 GB disk1
1: Applepartitionmap 31.5 KB disk1s1
2: Apple_Boot 128.0 MB disk1s3
3: Apple_RAID 148.9 GB disk1s4
/dev/disk2
#: type name size identifier
0: Applepartitionscheme *149.1 GB disk2
1: Applepartitionmap 31.5 KB disk2s1
2: AppleDriverOpenFirmware 512.0 KB disk2s2
3: AppleBootRAID 149.1 GB disk2s3
/dev/disk3
#: type name size identifier
0: Applepartitionscheme *74.5 GB disk3
1: Applepartitionmap 31.5 KB disk3s1
2: Apple_Driver43 28.0 KB disk3s2
3: Apple_Driver43 28.0 KB disk3s3
4: AppleDriverATA 28.0 KB disk3s4
5: AppleDriverATA 28.0 KB disk3s5
6: Apple_FWDriver 256.0 KB disk3s6
7: AppleDriverIOKit 256.0 KB disk3s7
8: Apple_Patches 256.0 KB disk3s8
9: Apple_HFS Laura 74.5 GB disk3s9
/dev/disk4
#: type name size identifier
0: *0.0 B disk4

Razorlance wrote:
Is it possible to just put the old SSD in the new laptop then?
Maybe, I just cannot say with authority. Even if they were physically the same, the question is what OSX is on the older SSD. If it is older than the one the new MBP came with, it will not work.
Ciao.

Creating a mirrored raid set with a hard drive that already has data on it.

I have a hard drive that I keep my photos on, and want to create a mirrored raid set that includes this drive, with its data, and another drive. How can I do this without erasing the drive with my photos on them? I am running 10.7.5 if that matters.
Thanks for any help.

Creating a Mirrored RAID reformats the drive and loads a substantial RAID driver and some tables onto it. When completed, the drive is inherently a member of a RAID set, and will continue to be so even if moved to another Mac.
because of this, you cannot create a RAID directly on a standard drive that contains data already in any reasonable, risk-free way.
To amplify what The Hatter has said above, Mirrored RAID is not Backup. Mirrored RAID only increases mean time to repair to keep a drive failure from becoming a Data Disaster. You still need a Backup. Mirrored RAID does not protect you from deletions from user error, crazy software, or "just because".
I run a mirrored RAID in my Home Server, which contains all the Users files for everyone in the Household. And I also recognize (after being burned by it) that Mirrored RAID is helpful, but not a sufficient Backup by itself. I back up the Users Drive automatically to an External drive using Time Machine. [So what I am advising is not just theoretical, I am living what I am advising.]
With WD Black 1TB and other very good drives in the under US$100 range, there is really no reason NOT to invest in several drives for such an undertaking.

Disk Utility gives error and does not rebuild mirrored RAID

After having a HDD fail on a mirrored RAID I replaced the HDD and attempted to rebuild. Disk Utility reports via Console that it can not find an Apple Boot partition to check size and then fails to repair the RAID. Details follow.
Mac OS X v.10.4.8 Server
Power Mac G3 (Blue & White)
512MB RAM
20GB ATA HDD – boot device on internal ATA bus
4x 160GB ATA HDDs - setup in RAID scheme on Sonnet ATA/133 PCI card
RAID configured using Mac OS X v.10.4.8's Disk Utility and is an Apple RAID version 2.
RAID scheme <from "diskutil checkRAID" cmd>:
Welcome to Darwin!
[myserver:~] myadminuser% diskutil checkRAID
RAID SETS
Name: Mirror_2
Unique ID: 5FF8AD5F-0892-482D-B430-C7069D63AFD2
Type: Mirror
Status: Online
Device Node: disk3
Apple RAID Version: 2
# Device Node UUID Status
0 disk0s3 1FB48B00-3E52-4C29-8F05-2ED8BDAE4544 Online
1 disk6s3 BF2E69C6-698E-4D6A-A2A9-FE8CDAD8A7B1 Online
Name: Mirror_1
Unique ID: B448A09D-EC10-41EE-BA45-4D4071A88EA5
Type: Mirror
Status: Degraded
Device Node: disk5
Apple RAID Version: 2
# Device Node UUID Status
1 disk2s3 09AD5705-CF67-48B3-8E31-79983BD4781A Online
0 disk4s3 23EB1952-8B18-4400-A6FE-22C2F707C097 Failed
Name: StorageRAID1
Unique ID: 2B8349AB-F553-4FD2-8440-C575791DA858
Type: Stripe
Status: Online
Device Node: disk7
Apple RAID Version: 2
# Device Node UUID Status
0 disk3 5FF8AD5F-0892-482D-B430-C7069D63AFD2 Online
1 disk5 B448A09D-EC10-41EE-BA45-4D4071A88EA5 Online
I configured this RAID scheme (two two drive mirrors striped together) according to this kbase document: http://docs.info.apple.com/article.html?artnum=304377
As shown in the above "diskutil checkRAID" output I have a failed HDD. So I replaced the HDD with another 160GB cold spare. I added the new drive to the mirror "Mirror_1" also known as disk5 and hit rebuild. Received the normal message that all data on the new drive I was adding would be erased.
I then receive the following error immediately in the Console Log:
Rebuilding RAID "Mirror_1"
2006-12-15 23:50:24.741 DiskManagementTool [375] WARNING: Could not find Apple Boot partition to check it's size, skipping disk5s-1s.
Rebuilding RAID slice "disk4s3"
Just to stem some confusion, the device ID disk4s3 has been used by the system for both the old failed HDD and the new replacement HDD.
The result of this attempted rebuild is I end up with all the data from Mirror_1 on the new HDD but the new HDD is not successfully added to the RAID, therefore Mirror_1 is still degraded and my problem not resolved.
I ran the appropriate rebuild cmd from both the GUI Disk Utility as described and from the CLI "diskutil repairMirror disk5 disk4s3" but no joy.
Any help would be greatly appreciated. This volume houses a large amount of important data including user home directories so while some offline time may be required data loss would not be very acceptable.
Thanks in advance and I will be happy to provide more information as necessary.

I guess doing it in Terminal would fail too:
diskutil repairMirror disk5 disk4

Maximum drive size for mirrored RAID

I'm want to set up a mirrored RAID with two 4TB drives that I have. When I put the drives in the tower (Mac Pro, OS 10.8.5) and open Disk Utility, the RAID button at the top does not show up for these drives. I only see First Aid, Erase, and Restore. Is there a max size for a drive that I'm exceeding? Or is it something else?

Hi - from the research I have done, there is a BUG in the OS. A solution is to boot with an older version of OS X and format the drive with the version of disk utlity on the older OS, or yank out the drive and put it in one of those 'drive toaster' type devices and format it EXTERNALLY. The problem seems to be localized when it's formatted with the drive INSIDE the MacPro.
You would figure that this would be a high priority fix, but NO. I went nuts for a few days trying to figure out WHY I could not see the RAID tab.
There is also third party software that has a more robust RAID solution. I have NOT tried it yet, but you should check it out.
http://www.softraid.com/
Alfred
PS: If you've resolved this problem, do share your findings here too!

Mirrored RAID: MediaKit reports block size error

I am trying to create a 2nd set up backup drives for my photos. I have two new iomega 2TB drives, which look essentially identical to drives I'm currently using as my primary backups as a mirrored RAID set.
I can start the process with freshly erased and reformatted drives (with the default mac format, extended, journaled, unencrypted, not case-sensitive). And after a minute or three, I see
"MediaKit reports block size error, usually caused by not being a multiple of 512."
The RAID options are Mirrored RAID, Mac extended journaled, and options settings are default.
I see several series of posts with complaints about encrypting RAIDs and disk block sizes, but not unencrypted errors. I actually started out trying to do this with the 2006 MBP running 10.6.8 and got a different error: "POSIX reports: the operation couldn't be completed. Operation not permitted." I wasn't sure whether the 2TB RAID I already have was set up iwth the older or newer computer--it was definitely before I put Lion on this one--so I tried this one and now have a different error.
Any idea what the problem might be?

Update: I spent some time on the phone with an Apple support RAID expert, and couldn't figure out what the error was; we couldn't bypass it by playing with partitions on the drives, or any of another couple of manuevers that I've already forgotten. He noted that his own searches were showing a lot of mentions of similar problems but only with Iomega drives, and he was finding the same links I found earlier about problems creating encrypted drives. Now trying to decide if it's worth throwing more good money after bad for a call with Iomega support, and waiting to see if the iomega forum is at all helpful.

Mirrored RAID taking too long for Data Rebuild

I have created a RAID 1 (Mirrored RAID) using Disk Utility in my Mac Pro. I have used 2 x 4TB WD Enterprise Grade HDDs. I copied 10 gb data on to this 4 TB RAID volume. Then removed one of the HDDs & installed in my other Mac Pro. It mounted as normal HDD & showed all the data that I had copied. To check if Disk Utility will rebuild the data, I deleted some part of this data (2 GBs out of 10 GBs) & installed this drive back in the system on which I had Created this RAID volume.
Initially I was surprised to find that Deleted data is now absent on this RAID volume. But on Launching Disk Utility it started rebuilding data on RAID volume.
BUT for Rebuilding 2 GB data estimated time shown by system was 9 hrs.
Is this NORMAL?
I intend to fill this 4 TB RAID volume with approximately 3.5 TB Data. In case one of the drive fails, how long should it take for Disk Utility to rebuild this amount of Data?
Is there any alternative way of speeding up this process?
Will Apple's RAID card help?
All your suggestions will be appreciated.
Thanks

I know this is an old thread but I'd be interested in what you came up with for a solution.
Here's my RAID journey thus far.
https://discussions.apple.com/message/25119317#25119317
Again, a gig of info and its taking 1 day 10 hours.
I hope theres a solution somewhere.
Drew

Mirrored Raid on Startup Drive?

Can I set up a Mirrored RAID with my Startup Drive without loosing the data?
I have a G5 Dual 1.8 running the latest OSX. I want to add a second internal HD, then setup a Mirrored RAID from my Startup Disk to my newly installed second internal drive. How do I set up this RAID without loosing anything on my startup drive? The new Drive will be the same size as my startup drive. I want the second drive as a backup startup drive.
Kevin Hawkins

Hi Kevin Hawkens;
What do you expact to gain by having a mirrored RAID?
Allan

Mirrored RAID drive removal.

I have 3 drives in my Xserve G5. 1 is 80GB and running as the system drive. the other 2 are 500GB drives which are both mirrored. I want to sacrifice the data redundancy and gain the extra 500GB for storage. I do not have a location to store the 400+GB of data that is stored on the mirrored RAID while I delete the raid. Is there a way to delete the RAID and then recover the data from one of the 2 drives and then format one of them to be blank? So far from what I am reading deleting a RAID set will make me lose my data I think... I am running the raid through Disk Utility as a software RAID.

Chris
If you delete the RAID1 with disk utility you will lose the data, I can only think of one way to do this-
Pull one of the RAID drives and let the RAID become degraded, data will still be there on one drive
Insert the pulled drive and format with disk utility
Transfer all data from degraded RAID to freshly formatted single drive
Once transferred, delete degraded RAID and format drive to use as extra space
Now doing this without a backup would be very dangerous, and I would suggest that all data should be moved to another drive before doing any of this.
I use software RAID configs all the time and would not recommend that anyone run a server without some form of redundancy, they have saved mine and my client's bacon many times.
Regards
Ed

Increasing Size of Mirrored RAID

Hi All,
I had a mirrored RAID set up with 2 500GB, and one by one rebuilt that with 2 1TB disks, but Finder and Disk Utility still report the logical drive as only 500GB. How can I get the system to recognize the extra space?
Bartram

Hi All,
I had a mirrored RAID set up with 2 500GB, and one by one rebuilt that with 2 1TB disks, but Finder and Disk Utility still report the logical drive as only 500GB. How can I get the system to recognize the extra space?
Bartram

Mirro Raid can you use a single 4TB disk with 2 partitions for mirrored raid ?

Hello,
I have a new 4TB hardrive.
After lots of reading, i was thinking that i could partician the drive to 2 (2TB) Then create mirror raid.
Essentially thinking that i would have photos on one of the (2TB particions) and they would mirror on the other ?? as a double copy storage.
I can partician okay and the try to drag the two particians onto the "mirror raid set" and ithe following message displays :
"Can't add Seagate expansion disk" to the raid set because another volume from this disk is already part of the RAID set"
I'm now thinking i need to purchase another 4tb hardrive for this to work ?
Or if you "mirror raid set" is it actually particioning the drive and creating a copy ?
Forgive me... i'm not really very up skilled with disk utility, and basically just don't understand.
Looking forward to some help and advise
warm regards Tracy Gr

It doesn't make any sense to mirror on the same drive. The idea behind mirroring is that should one disk in the raid set fail your data is safe on the other disk. Mirroring to partitions, if it's even possible, would only bring you disaster when the drive fails because you would lose the complete raid set and all of your data. If you insist on mirroring buy another drive.

Workaround to use drives with 4096b block for mirrored RAID?

I have 2 Hitachi 2TB Drives. One is a few months old and uses 512b blocks, the other is the same model, but newer and uses 4096b blocks.
When I try to set up the RAID Set I get the error: MediaKit reports block size error, usually caused by not being a multiple of 512.
From reading the message board, it looks like this a known bug when trying to encrypt drives with 4K block sizes or add them to a RAID Array.
Is there any way to set these up as a mirrored RAID array other than waiting for apple to fix the problem? Are there third party apps that can be used to fix this problem?
Thank you for your time.

I have the exact same problem, and until Apple solves this bug, I no longer have a hard drive large enoug for my Time Machine back-ups. I have submitted the bug, but I really need a solution. Please help!

Concatenated Mirrored RAIDs

Similar Messages

Maybe you are looking for