Mirrored RAID Failed

I have an xserve with three drives. Bay one is a regular single boot volume but bays 2 & 3 are a mirrored RAID pair. I got a flashing yellow light yesterday and ran Disk Utility. It showed the RAID pair as having an error. I ran First Aid and it now reports that the volume is OK but when I look at the RAID panel only one physical disk is listed. The volume still functions ok, the server is working fine and the yellow light is not flashing now - but I guess this means that I do not have a mirrored RAID pair anymore.
How should I go about returning my RAID to a mirrored pair? How can I identify which of the two physical disks has failed? (I don't want to pull out the wrong one!) Can I slot in a new disk and have it added into the RAID as a replacement?

Do you have a backup of that RAID?
If yes I would rebuild the RAID. From what you are saying I would not trust it any more. When you do that then you can test each disk by formating it and then trying to copy data to the drive. You can then see if one is not working right or if they both are fine.

Similar Messages

Xserve - Mirrored RAID Failed? Degraded? Confused...

Hi,
Can anyone shed some light on this situation please? Disk utility tells me one thing and Server Monitor tells me another.
I have an X-Serve with 3 drives and a Mirrored RAID Set running 10.5.8.
Server Monitor is showing a yellow status for disk 1 and disk 2. Raid Status: Degraded (Mirror) Pre-failure Warning: No Warnings
Disk Utility on the other hand shows that the Mirrored RAID sets are Degraded because disk2s4 = Failed and disk2s2 = Failed.
Running disk utility commands in terminal also show disk2s4 and disk2s2 as Failed.
I have not yet tried to Rebuild or eject / reconnect the disk. The only thing I've really done is some research and rebooted the server.
It sounds like disk 2 has failed. Is there any way to confirm it's dead? Are there any serious risks of trying to rebuild?
Thanks.
- F4st

I'm not sure why you think you're seeing conflicting information…
Server Monitor is showing a yellow status for disk 1 and disk 2. Raid Status: Degraded (Mirror) Pre-failure Warning: No Warnings
OK, So Server Monitor says the RAID is in a degraded state…
Disk Utility […] shows that the Mirrored RAID sets are Degraded because disk2s4 = Failed and disk2s2 = Failed
Running disk utility commands in terminal also show disk2s4 and disk2s2 as Failed
I don't see this is anything different. All three methods are telling you disk2 has failed and your mirror is relying on disk1 for all activity.
Is there any way to confirm it's dead?
Umm.. you mean other than Server Monitor, Disk Utility.app and diskutil?
Face it, it's dead. It's had it.
Are there any serious risks of trying to rebuild?
Sure. If the disk is dead, it's entirely possible that rebuilding the array on that disk will fail. You run the risk of a problem on disk1 and then all your data is gone.
My advice: Replace disk2 as soon as possible. If not sooner.

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.

Mirrored RAID degraded, upper slice shows "failed" but drive passes verify

Hello,
I have a mid 2010 Mac Mini running Mountain Lion and Server. The Mirrored RAID is showing degraded and that the upper slice has failed. However, doing a verify of the drive does not report any problems.
Is there a way to determine if this is just a RAID management issue? I've considered rebooting into single user mode and running fsck but not sure what else it will tell me?
Is it safe for me to click on the slice that is showing "failed" and hit rebuitd? (after verifying a good back up of course). I started down this path but didn't like the warning OS X provided; it was not crystal clear which physical drive it would erease the data from.
Thanks,
Tim

I meant to add that boot up reports:
AppleRAIDSet: addMember() detected expired sequenceNumber (1) for member _______big id_____
AppleRAID::restartSet - restarting set "Harddrive name" (______another big id_____)
CoreStorage: fsck_cs has finished for group " ______yet another big id________" with status 0x00
CoreStorageFamily::unlockVEKs) failed to unwrap the vek, status = e00002bc
- Tim

Mirrorred RAID Rebuild Failing

Hello,
I had a mirrored raid setup on 10.6.7, everything was working great for the last month, then today I went into disk utility and it said one drive failed. After checking the drive, there didn't seem to be any problem with its operation, so I can only assume it was a software/communication failure.
Clicking the rebuild button resulted in this error:
Rebuilding RAID set failed with the error:
POSIX reports: The operation couldn't be completed. Operation not permitted.
So I tried removing a disk, that also failed with the same error.
I then erased the failed drive which automatically removes it from the RAID configuration. Now when I try to add it back to the configuration I get the exact same error.
Has any experienced this issue and have any suggestions on how to get RAID back online?
Thanks in advance!
Michael

Thanks for your reply.
Yes, I am sure that the drives are working. I do not know what caused one of the drives to 'fail' as far as disk utility was concerned - but it was online when I checked it again.
I had issues while originally creating the RAID configuration, similar POSIX issues.
I have managed to get the configuration back online using the SoftRAID, but I am unable to create any new RAID configurations or modify existing ones using Disk Utility. Is it possible its an issue with POSIX and the drive USB drivers? Though I have tried with 3 or 4 different brand drives.
SoftRAID allows the drive set to be converted to a Disk Utility set after creating/repairing it - so thats what I have done for now.
I will try to setup/repair this all again once I have Lion installed and see if they fixed it in that version.
Any suggestions on how to get Disk Utility's RAID configuration on a Intel Core 2 Duo Mac Mini would be appreciated. I have filed a bug report with Apple as well. SoftRAID was a suggested alternative to a few other posts on the discussions for similar issues.
Michael

MacMini Mirror RAID degradated, 2nd slice failed

I have a Mac Mini Server Late 2012, with the following specs:
- 2.3 GHZ I7
- 10 GB RAM (1x2 GB, 1x8 GB)
- Dual 1 TB HD 5.400 RPM
- OSX Maverick 10.9.5
- Mirror RAID
Apparently an error with OwnCloud caused the disk to get almost full. I found the problem, deleted the files and then ran disk utility and, for my surprise, I found the raid hd (serverhd) marked as "degradated" and the 2nd disk marked as "failed":
Running diskutil on terminal confirms that the 2nd slice as "failed":
My questions are:
1. Does the failed status on disk1s2 means that the disk PHYSICALLY failed or that the data in the disk doesn't match with the one in the 1st disk?
2. If this is a data failure, how can I rebuild the data in the 2nd disk? By selecting the failed disk in disk utility and hitting Rebuild?
TIA
Victor Espina

I finally solved this issue:
1. Made a full copy of server's HD in a external disk using CCC
2. Changed boot drive to use the external disk. In theory, this was not needed but I prefered to boot from a different disk just in case.
3. Once booted from the external disk, when to Disk Utility and "demote" the failed disk from the RAID array.
4. Using Disk Utility, I reformated the failed disk and added again to the RAID set (to do this, select first the RAID set and then drag & drop the disk from the left panel)
5. Once the disk was added to the RAID set, I pressed Rebuild and waited until de RAID set was rebuilt.
6. Then I set the HD as the boot drive and restarted the server
Thanks all for your help on this.
Victor Espina

Which hard drive to choose when a hard drive failed from mirrored raid

this is my mirrored raid set up from 4 ext HD to make a total of 2 mirrored ext HD raids. In one set, a HD is out of sync and has failed. I chose auto rebuild when I create the raids but it did not occurred. question-Which HD do I chose to rebuld when I use disk utility? Please see picture below. thank you.

any suggestion? or am i in the wrong discussion board.

Software RAID failing constantly

Dear all,
I need help as I cannot work out what is going wrong the the Mirrored RAID i set up.
I bought 2 x 1TB drives and setup Mirrored RAID (software) through the GUI Disk Utility Application. I assumed it would all "just work".
After about a month the RAID failied. It happened after I ran TechTool Pro 5. Could this have caused permanent damage which leads me to where I am today (see below)? I unplugged the drives and plugged into my laptop (I don't know why I didn't just unplug and plug them into the Mac Mini they were in). Anyway it came up saying "Rebuilding" and it took about 9 hours. All was good again.
Until early October 2009 when Disk Utility reported that the RAID was "degraded" and one of the drives had "failed".
I was pretty shocked as it was a new drive. I thought the best thing to do would be to get a new 1TB drive to rebuild the RAID and then deal with the failed drive.
It took over 2 weeks to get the new drive and enclosure (long story). I setup the new drive last night, plugged it in and the "Rebuilding" message came up with the same "it will take 9 hours message".
I left it over night and when I got up Disk Utility told me that the older drive of the two has "failed". There has to be something weird going on here and this is where I need your help.
Configuration
1. The drives are 1TB Hitachi 3200rpm SATA I/II, 32 MB Cache drives
2. The 'old' enclosure is an Icecube G2 SuperS 800/400/USB2/eSata 3.5" Enclosure
3. The 'new' enclosure is an OWC Mercury Elite-AL, Quad Interface eSata/FW 400/FW 800/USB 2/USB 1
4. The Mac Mini only has one FW800 port and I connect the 2 drives up in serial.
<hr />
Here is the behaviour I'm seeing now.
I'll start with both drives off and turn both on.
1. Both drives mount in Disk Util
2. 20 seconds later a message comes up about rebuilding slices for "disk1 ... ?" and "disk (null)" and disk util crashed 2 seconds later (thus why didn't catch all of the message)
3. I turn to the terminal:
bsmith@kanga ~ $ diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *298.1 Gi disk0
1: EFI 200.0 Mi disk0s1
2: Apple_HFS Mini 297.8 Gi disk0s2
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *931.5 Gi disk1
1: EFI 200.0 Mi disk1s1
2: Apple_RAID 931.2 Gi disk1s2
3: Apple_Boot Boot OSX 128.0 Mi disk1s3
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *931.5 Gi disk2
1: EFI 200.0 Mi disk2s1
2: Apple_RAID 931.2 Gi disk2s2
3: Apple_Boot Boot OSX 128.0 Mi disk2s3
/dev/disk3
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS terra *931.2 Gi disk3
bsmith@kanga ~ $
bsmith@kanga ~ $ sudo diskutil listRAID
Password:
RAID SETS
===============================================================================
Name: terra
Unique ID: 2AC46C49-5F0B-4BD5-B1FE-C322A6F51DD9
Type: Mirror
Status: Degraded
Size: 999860895744 B
Rebuild: automatic
Device Node: disk3
Apple RAID Version: 2
# Device Node UUID Status
0 disk1s2 A12D748F-0779-4217-8C75-B31D9AE45B4E 0% (Rebuilding)
1 disk2s2 CF03D24E-AB5D-4F86-A7B1-26A1F4589CB7 Online
===============================================================================
bsmith@kanga ~ $
Run it again 10 seconds later:
bsmith@kanga ~ $ diskutil list
It just hangs.
bsmith@kanga ~ $ sudo diskutil listRAID
It just hangs.
4. Now I turn off the 'old' drive and look at the terminal (that was hanging). When I turn it off I'm told (through the Hardware Growler Growl extension to show the status of hardware) that the old drive ("Macpower"), the new drive ("OWC") and the RAID disk ("terra") have all unmounted. The diskutil commands follow.
bsmith@kanga ~ $ diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *298.1 Gi disk0
1: EFI 200.0 Mi disk0s1
2: Apple_HFS Mini 297.8 Gi disk0s2
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *0.0 B disk1
1: EFI 200.0 Mi disk1s1
2: Apple_RAID 931.2 Gi disk1s2
3: Apple_Boot Boot OSX 128.0 Mi disk1s3
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *931.5 Gi disk2
/dev/disk3
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS terra *931.2 Gi disk3
bsmith@kanga ~ $
bsmith@kanga ~ $ sudo diskutil listRAID
RAID SETS
===============================================================================
Name: terra
Unique ID: 2AC46C49-5F0B-4BD5-B1FE-C322A6F51DD9
Type: Mirror
Status: Degraded
Size: 319728959488 B
Rebuild: automatic
Device Node: disk3
Apple RAID Version: 2
# Device Node UUID Status
0 disk1s2 A12D748F-0779-4217-8C75-B31D9AE45B4E 0% (Rebuilding)
1 -none- CF03D24E-AB5D-4F86-A7B1-26A1F4589CB7 Online
===============================================================================
bsmith@kanga ~ $
I don't know alot about this output, though its weird that disk2 is still in the list but only shows the GUIDpartitionscheme. And its interesting that disk1 is also in the list but shows 0.0B against the GUIDpartitionscheme for it.
5. Just for kicks I turn off the 'new' drive aswell and run the commands again. When i do it Hardware Growler doesn't say anything has unmounted (I guess since they all did so before).
bsmith@kanga ~ $ diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *298.1 Gi disk0
1: EFI 200.0 Mi disk0s1
2: Apple_HFS Mini 297.8 Gi disk0s2
bsmith@kanga ~ $ sudo diskutil listRAID
Password:
No RAID sets found
As expected I guess.
6. Now I'll turn both drives back on and confirm I get back to the same state I was in before after both drives were turned on.
This time I get the Hardware Growler message that both drives have mounted followed by the RAID drive about 20 seconds later.
bsmith@kanga ~ $ diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *298.1 Gi disk0
1: EFI 200.0 Mi disk0s1
2: Apple_HFS Mini 297.8 Gi disk0s2
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *931.5 Gi disk1
1: EFI 200.0 Mi disk1s1
2: Apple_RAID 931.2 Gi disk1s2
3: Apple_Boot Boot OSX 128.0 Mi disk1s3
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *931.5 Gi disk2
1: EFI 200.0 Mi disk2s1
2: Apple_RAID 931.2 Gi disk2s2
3: Apple_Boot Boot OSX 128.0 Mi disk2s3
/dev/disk3
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS terra *931.2 Gi disk3
bsmith@kanga ~ $
bsmith@kanga ~ $ sudo diskutil listRAID
RAID SETS
===============================================================================
Name: terra
Unique ID: 2AC46C49-5F0B-4BD5-B1FE-C322A6F51DD9
Type: Mirror
Status: Degraded
Size: 999860895744 B
Rebuild: automatic
Device Node: disk3
Apple RAID Version: 2
# Device Node UUID Status
0 disk1s2 A12D748F-0779-4217-8C75-B31D9AE45B4E 0% (Rebuilding)
1 disk2s2 CF03D24E-AB5D-4F86-A7B1-26A1F4589CB7 Online
===============================================================================
bsmith@kanga ~ $
Now let me run the commands again:
MMM, the exact same result is returned - it didn't hang this time.
It's 21:44, I'll leave this a while and see if the rebuilding continues.
Its 13 mins later and this time the commands are just hanging. Before I went away at 21:44 the lights on the front of the drives where flashing showing something was happening. They had stopped by the time I returned.
7. Now I turn off the 'new' drive and run the terminal commands again. When I turn it off I'm told by Hardware Growler that the new drive ("OWC") and the RAID disk ("terra") have both unmounted. Last time (when the 'old' drive was turned off) Growler told me all 3 drives unmounted. The diskutil commands now show.
bsmith@kanga ~ $ diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *298.1 Gi disk0
1: EFI 200.0 Mi disk0s1
2: Apple_HFS Mini 297.8 Gi disk0s2
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *931.5 Gi disk1
It hangs at this point and hasn't completed yet.
bsmith@kanga ~ $ sudo diskutil listRAID
Password:
RAID SETS
===============================================================================
Name: terra
Unique ID: 2AC46C49-5F0B-4BD5-B1FE-C322A6F51DD9
Type: Mirror
Status: Offline
Size: 999860895744 B
Rebuild: automatic
Apple RAID Version: 2
# Device Node UUID Status
0 disk1s2 A12D748F-0779-4217-8C75-B31D9AE45B4E Failed
0 -none- CF03D24E-AB5D-4F86-A7B1-26A1F4589CB7 Missing/Damaged
===============================================================================
bsmith@kanga ~ $
So HELP PLEASE!. Does the above provide enough information to suggest to someone with more knowledge than me about this, what is going on and what can I do to fix this? Let me know if there are any more tests I can run.
I have a backup of the data so can erase and recreate the RAID drive. But what would stop this happening again? Could it have been TechTools Pro 5 which was running when the problem first happened that caused some permanent damage?
Any and all help appreciated.
Thank you,
Brooke

Thanks ridogi and Antonio for your replies,
For clarification, both drives have dual FW 800 to allow them to be connected. No FW 400 involved (I'm not that silly .
I can't say i've done extensive research into setting up RAID drives but I've never come across advice to not use multiple external drives. Here is an extract from a Nov 2007 MacTech article on using RAID for backup:
{quote}
The Desktop Mac User:
The second user I want to look at is the professional who relies on his desktop Mac for his business. He is a lawyer, developer, architect or other professional whose business relies totally on the contents of his computer. If he loses the files on his computer, his business will really suffer. In addition, the time lost when dealing with a failed hard disk is money down the drain. This user relies on a three disk mirror volume. His Mac has two internal SATA disks which are used as the primary and secondary disks of a mirror volume. If one of the disks fails at any given point, the other one will take over and become the new primary disk, so his files are always protected from a hard disk failure. The third disk is an external FireWire disk which is also a secondary disk. It is stored offsite (either at home in a fireproof safe or at another safe location). Every Friday, he brings this third disk into his office and connects it to his desktop Mac. Once this disk is connected, a mirror rebuild starts automatically. He can perform this rebuild as he continues to use his Mac during the day. At the end of the day, when he shuts his Mac down, he disconnects his external secondary disk and returns it to its offsite location. This offsite secondary disk becomes his insurance against his building getting broken into or his building burning down. Like the laptop user, if his Mac gets destroyed, he can just purchase a replacement Mac and then boot up from his external secondary disk. At most, he will use one week's worth of work.
{quote}
So I just assumed it is ok to use external drives. This is discussing a software product called SoftRAID and perhaps that is able to handle the situation. Or perhaps one external drive is ok???
My plan, developed when deciding to buy the Mac Mini April 2009 was to amortize costs by buying external drives first for doing backups and then buying a NAS within 12 months. I guess I should have just gone the NAS.
However ridogi I see you've recommended WiebeTech which don't seem to have NAS devices but DAS (direct attached storage) as the devices are connected directly to a network machine via Firewire etc. (Whereas NAS connects via the Network - I'd connect such a device to the Airport wireless router). Do you prefer DAS over NAS? I guess the downside of NAS is that the complexity is somewhat greater.
And reading http://www.wiebetech.com/just-say-no-to-nas/ they say:
{quote}
Let's face it - Networked or "shared" storage is a great feature but most NAS devices are just too slow for many applications. 3MB/s for a NAS device is common and 10MB/s is considered fast. Direct Attached Storage (DAS) performs much faster while still having the ability to be "shared". The RTX400-QR can transfer data to your computer at speeds exceeding 100MB/s.
{quote}
How can this be? If connected via Gigabit ethernet (128MB/s) then isn't that faster?
Though it is true that if you connect via Wifi then the best speeds you are going to achieve is 6.75 MB/s (802.11g) or 17.5 MB/s (802.11n).
Of course the speed advantages for DAS are only going to be on the machine its connected to as the other machines will connect to it (via the machine its on) over the network anyway!
Why I like the idea of NAS is to move the drives away from the Mini (noise and powerpoint reasons), make it easier to share with other Macs/PCs in the house (including via SMB) and I have a vague hope that this might stop the delay caused by the connected external drives spinning up when an open/save dialog box is activated (or is this just me?!).
Your thoughts appreciated! And thanks for the help so far.
Cheers,
Brooke

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

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

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.

Offline Disc In Degraded Mirrored RAID Set

I have a 2 disc (300GB each) mirrored RAID set that has worked fine up until recently. One slice appeared failed so I attempted to rebuild it. 7 hours later it still showed up as failed. I attempted a rebuild once more and the same result. I then shut everything down and re-booted my whole system. Now the RAID set is still degraded but the slice now shows up as offline as opposed to failed.
I checked the connections and it's all connected fine.
I have run First Aid several times and no repairs were necessary.
Anyway I can get this back 'online'?
If not, can I delete it, repair it and if it's repaired add it back to the RAID set?

It sounds like one of the drives in the mirrored set has lost its mind (i.e., failed).
This is exactly the situation Mirrored RAID is good for.
Remove the failed drive, insert your spare drive of the same or larger size, and assign it as a spare. Then you should be able to get the RAID to rebuild onto the spare and bring it up to date in the next half-a-day or so. Then the mirror will show as working again.
Make sure your Backup is up-to-date. A second failure now (before the array has rebuilt) will give you data loss.

Re-create a mirrored RAID after restoring backup

As a follow-up on my thread http://discussions.apple.com/thread.jspa?threadID=833779&tstart=0 :
On a XServe G5 with OS X Server 10.4.8 and a two-drive mirrored RAID I do backups by cloning the RAID onto an other disk (in bay three) using Intego's Personal Backup X4.
Now it may happen that there is some kind of data loss or an other emergency case that urges me to boot from the cloned HD. I would do this by simply removing the HD in bay one and replacing it with the clone, then restart the server (second HD of the RAID1 remains in bay two).
The information I got until yet says that the mirrored RAID is then broken and needs to be completely re-build. Is this correct so far ? I originally assumed that the clone "remembers" that it was part of a RAID system before and rebuilds automatically with the second HD still in place. Very likely wrong ?
So if I need to rebuild the clone from scratch, which steps do I follow exactly ? As far as I understand I have two choices:
(1)
Via command line (as root): diskutil createRAID mirror <set name> Journaled HFS+ <device identifier disk1> <device identifier disk2>
<set name>: Would be volume name of the RAID to create, right ?
<device identifier disk1/2>: What is this and how to determine ?
(2)
Via disk utility: Select one disk (first line on the left disk/volume list, e.g. "76,2 GB Hitachi 123ABC"), click in "RAID" tab, do settings.
Then drag & drop each harddisk from the left to the right list (again, the first line of each disk entry). Finally creating the RAID by clicking at the button "Generate".
I'm not sure, although I would likely handle this with the disk utility, it appears easier to me using the diskutil command in terminal. But maybe I simply lack of explaining the GUI... let me know how to post images and I will add some screenshots here.
Well, if my proceedings are too complex and there is something easier, please let me know. I'm open for everything.

>This part of my question originally referred to the fact that when booting from the cloned backup in bay one while still having the second disk of the old RAID in bay two, it could occur that the OS rebuilds the RAID by using the data on the remaining mirror disk in bay two, couldn't ? This would be not desired, because the data on that disk would be no longer usable. So just for clarification, not that we have a misunderstanding in this point.
I see what you're getting at, and I don't believe it's an issue.
Given three disks, disk0, disk1 and disk2, where disk0 and disk1 are mirrored and that mirror fails, the OS will not rebuild the mirror using disk1 and any other disk. It won't arbitrarily choose any disk in the system to rebuild on - you have to specifically mark as disk as usable, either by enabling auto-rebuild and adding a spare disk to the array, or by using 'repairMirror' and specifying the disk to use.
In any case, if you reboot the system from disk2, there is no way it will rebuild the array using that disk since that disk is the active boot drive and can not be unmounted (which is necessary before being added to an array).
So, no, there is no chance that the system will auto-rebuild the working half of the mirror with your backup disk.
>Okay, let's summarize... I would follow this procedure in order to boot from the cloned backup and build a new RAID:
1. Remove both disks from the XServe.
2. Insert the cloned backup disk and boot.
3. Open terminal, su root, execute:
diskutil enableRAID disk0
diskutil repairMirror disk0 disk1
This is not correct.
When you 'enableRAID disk0' the OS will create a new, virtual disk (likely 'disk2'). This is the mirror array (currently consisting of only one drive), and it is this virtual disk that you need to specify as the mirror to be repaired.
So, given disk0 and disk1 as being the physical disks in the server, the steps are more likely to be:
<pre class=command>diskutil enableRAID disk0</pre>
(this creates a new, virtual disk2)
<pre class=command>diskutil repairMirror disk2 disk1</pre>
(this adds physical disk1 to the degraded mirror disk2)
When complete disk2 will be a mirror RAID consisting of disk0 and disk1.
>When using "diskutil enableRAID", I cannot determine the label of the RAID as I would do with "diskutil createRAID" (in command line manual this is referred to "setname"). Which setname does my "new" RAID system get, a default one ?
You know, I have no idea
I've never noticed this before. If I think about it, I'd guess that the setname is based on the source disk name.
>> If you add a drive to a RAID it gets reformatted, so it doesn't matter what's
on it.
Even if it was part of the RAID system before (the original disk in bay two) ? It could still have the RAID information on it and try to rebuild RAID when getting mounted, couldn't ?
No. See my comments above. The OS won't auto-rebuild unless a) the RAID is set to auto-rebuild and b) there is a spare disk in the array. If either of those two conditions are not true then the disk acts as a degraded mirror and can be reformatted/reallocated as you like.

Mirrored Raid Set

I have two disks arranged as a mirrored RAID set and wonder how I will know when one of the disks fails and which one it is.

Mirrored RAID is sort of worthless for most all users as anything bad happens gets immediately copied to the other drive.
Your better off with scheduled clones, this way every so often it will remind you to hook it up and update it, or leave one hooked up and it will update itself.
You get both hardware AND software protection as you only update when you know it's good.
Also you can keep several clones backdated, and they are all independently bootable.
Most commonly used backup methods

Mirrored RAID set has degraded following power outage.

Hello,
Following a recent power outage our Mac Pro running Leopard OSX Server with 2 x 1TB discs in a Mirroring RAID configuration (with an installed RAID card) developed a 'severe error' message.
The Raid Set R0-1 has a Viable (degraded) status.
Drive One (or bay 1) is 'Good' and 'Assigned'
Drive Two is 'Good' but with the State - 'Roaming'
Also, the events display describes the failure of a drive 3 (there isn't one) and that the R0-1 is Degraded and no spare is available.
So, we're a little confused.
1. Is the Drive 2 no longer part of the RAID mirror (i.e. Roaming)
OR
2. Something more significant has happened hence the bogus Drive 3 message?
Any suggestions or advice would be much appreciated as always.
Thanks
Steve

Yes. Verification with the GUI tool is the first step. But... hmm, if you are dropping communications with the card, that is not a good sign. Make sure you have a backup and then try a PMU reset on the system. Maybe there is something wacky in the power manager. Then try any/all of these from Terminal to get more information:
raidutil list status
raidutil list eventinfo
raidutil list raidsetinfo
This should provide feedback. If these commands fail, then I fear that the card is not responding. Do you have AppleCare? It might be time to call for a replacement card.
Hope this helps

Mirrored RAID Failed

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