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.

Similar Messages

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.

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 Set Questions

I initially set up a mirrored RAID set up on my system drive as a means of backing up my files. I've since decided I'd like to use Time Machine instead. When I try and break up the RAID set using Disk Utility, a lock icon appears next to the RAID set and I'm unable to "delete" the set. My guess is that I need to reboot off a different system, but since Lion didn't come with an install disc, and since Lion doesn't set up a Recovery HD on RAID sets, how would I go about unlinking this mirrored RAID set?
Conversely, I inadvertantly unlinked a different RAID set and would like to reconnect them, but Disk Utility says it'll erase all the data on the drives before it establishes the connection. Is there a way to reconnect a mirrored RAID set that has been disconnected?

For the first question, go back to the App Store download Lion again but before it begins the install stop the process and create a flash drive installer. See How to make a bootable Lion install disc or drive .
Remember you have to make sure the install process doesn;t proceed because once Lion is installed the installer app will be removed from your HD.
Sorry can;t help with the second question.
regards

Degraded mirrored raid- won't rebuild

I've had 2 500 gig drives mirrored. When I set up the drives I did not check "automatically rebuild".
I just discovered ( not too long after installing Leopard) that one slice was "damaged" and the raid was degraded. I tried to rebuild, but got an error message that said disk utility was unable to recognize the filesystem. I finally erased the "damaged" drive, verified it and am ready to try rebuilding the set, but don't want to lose data from the remaining drive from the original raid.
How should I proceed?
Thanks-
Ford

Well I'm sure VERY few people have multiples of EVERYTHING. I still have my data.
All I want to do is mirror a fresh drive with the other drive that was part of a mirrored raid set. That should be possible... it seems...
Please don't admonish me for not having more backups. I have a total of 1.25 terabytes of HD space with a lot of redundancy.

Really Ignore Degraded Mirror RAID ?

Hi, I just became responsible for a studio with a RAID system -- I'm new to this so please bear with me.
Server Monitor shows that 2 drives are degraded. It seems that these are slices of a Type 1 (Mirror) RAID set. The symptoms match the following linked document exactly (which says Server Monitor may erroneously report degraded status of Journaled drive, and you can ignore if Disk Utility says it's OK):
http://docs.info.apple.com/article.html?artnum=107406
However, I can't say for sure that Disk Utility is giving me a green light on this RAID set. Disk Utility (the GUI application) says the RAID set and the slices are degraded. But Disk Verify comes through fine. Also "diskutil checkRAID" says that Status is Degraded but that both disks in set are "OK".
So do I worry about this or not?
Any and All Help Much APPRECIATED!

I have seen this issue on a couple of Xserve's
This is how I went about fixing-
Get someone in front of Xserve
Identify which one the 2 drives is NOT working IE- no blue activity light
Pull that drive and break RAID
Insert drive
Rebuild mirror, see this article for info-
http://docs.info.apple.com/article.html?artnum=106987
There is a way to rebuild the mirror in Disk Utility, I cannot find any info from Apple on this but i have used a few times.
On one Xserve I have done this at least 3 times, I have completely rebuilt the RAID and re-installed the OS and it still does it occasionally.
Ed

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.

Mirrored RAID set deletion

Hi all,
I've set up two USB disks as a mirrored RAID set connected to my MacBook.
Now, I want to remove this RAID set (since it doesn't work so well for me).
In the manuals, Disk Utility is said to split nicely a mirrored RAID set, resulting in two disks with the same contents, when removing a mirrored RAID set.
However, when I try to do it, Disk Utility warns me that all data on the disks will be lost (which should not be the case...).
I can't afford to loose all data (120GB of photos), and I can't easily make a backup (120GB of data is tough to backup !)
Who should I trust ? Disk Utility or the manual for Disk Utility ?
Will my data be lost or not when I delete this mirrored RAID set ?
I need an authoritative answer... Could someone help me ?
Thanks,
Chris

Thanks for your advice... but if no RAID disk is plugged in, the RAID does NOT show in Disk Utility.
As I understand it, the partition scheme is different when using RAID... So a disk that is part of a RAID set has to be modified to get out of the mirror...
But it seems Disk Utility cannot disconnect a single disk from the RAID.
My RAID is now out of sync, and I won't attempt to resync it again...
So I would like to remove the whole RAID thing, and just get two disks, one that will be reformated, and one where all the data should be kept...
Later this week, I'll have access to another (afaik Firewire) disk... So I'll make a backup and simply try to delete the RAID... If it goes wild, I'll have that backup to recover.
I'll keep you posted if I can.
However, things should be made clear somewhere : either in the docs or in Disk Utility... I submitted some comments about the documentation on apple's website.
Bye
Chris

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

See HDD failed in Mirrored RAID Set

Could you please kindly tell what steps should I do to fix failed Harddisk as below? Many Thanks.

Thanks for the answer. Do you have any pointers to how to identify from device name, which physical hard disk it is? For example, I have a RAID1 mirror set, the devices are disk1s3 (failed) and disk4s2. These are partitions on 2 different external disks. How do I know which one disk1s3 is? Is there a way to reconcile it with the hardware?
I suppose I could unplug one of the disks and see what happens, but that would be disruptive and extreme. What would happen to the RAID set, what if Time Machine is running to the mirror?

Destroyed mirror RAID (1), Want to get data, but how?

I had a degraded mirrored RAID set that was functioning in its degraded state - reads and writes were no problem.
I thought that if I used DiskUtility to destroy the RAID, it would convert the drives to normal drives, and I would have access to each individually, but this was not the case. I also thought the data was backed up, but this was not the case.
I used the minus sign in the RAID tab DiskUtility to destroy the RAID. There are now 2 drives, but neither is able to be mounted:
bash-3.2# diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *698.6 Gi disk0
1: EFI 200.0 Mi disk0s1
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: GUIDpartitionscheme *698.6 Gi disk2
1: EFI 200.0 Mi disk2s1
2: Apple_HFS 698.3 Gi disk2s2
If I try to verify the first disk:
bash-3.2# diskutil verifyDisk disk0
Error encountered attempting to verify/repair disk0: Unrecognized filesystem (-9958)
but if I try to mount it, it thinks the mount is successful, but nothing new shows up on the Desktop, nor with "df"
bash-3.2# diskutil mountDisk disk0
Volume(s) mounted successfully
in reality, the drive is NOT "mounted successfully."
disk2 is in worse shape, as the OS is not even fooled into thinking it is mountable:
bash-3.2# diskutil mountDisk disk2
One or more volume(s) failed to mount
So I am trying to put my recovery efforts toward disk0.
Any ideas on how to mount the drive and get data off of it?

I had the same issue a few months back.
1 drive of my mirroed raid died. So I took the working drive out of that box and put it in a FW enclosure. It mounted fine. However after converting it back to a regular volume it would not mount. I tried everything thing I exhausted google searches.
the only fix was to reinitialise the drive. Luckily I had the data backed up elsewhere.

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.

Possible to convert a mirrored RAID boot drive to a single disc boot drive

hi ... i made the mistake of installing my Macpro with a RAID on the first two drive bays as a startup disc. Although this doesn't pose any problems per se i would like to have a single disc startup drive now but i do not have the time or courage to re-install and re-configure everything (installation&config with all software takes 3 days due to the huge number of software i have on this machine).
is it possible (and how) to get rid of the RAID and convert one of the discs to a normal startup volume so i can reformat the second disc and use it as a work drive ? Since the 'mirrored' drives both contaion a full startup drive this should be possible i think but could not find any info on this.
thx for any help with this ...

hey .. funny how expert opinions vary ... i have a handfull of IT and software RAID experts who disagree with you ... in my case, i'd rather get rid of it ... ( however i still have to find a solution to clone my boot drive that works flawlessly with all my software ... )
anyways ... how exactly do i go about splitting the RAID, to make sure i don't mess it up ....
1. restart from CD
2. Delete the mirrored RAID set
3. remove one of the HDs with the raid slice on it (i'll keep it as a backup 4 the moment just in case)
4. restart from the remaining slice disc
5. ... ?
do i need to do anything specific ... ? what about the name of the Volume .. for the moment my startup disk (the RAID) is called 'BootRAID' ... the slices are called 'RAID Slice (disk0s2)' and 'RAID Slice (disk1s2)' .. in order for everything to work properly, don't i have to rename the new startup disk ?
i'm scared ...
here's a screenshot of my setup: http://kinkajou.net/diskUtility_RAID.jpg
<Edited by Moderator>

My mirrored RAID config shows degraded

My simple mirror RAID set is noted as degraded in Disk Utility, and one of the drives is doing frequent drive arm recalibrations. This drive set contains all my iTunes and iPhoto files. Time to replace a drive or two?
I'll copy the data to my desktop drive but then what?
- How do I diagnose which drive is the bad one?
- How do I know that in fact there is a bad one? Hard error or correctable soft error?
- How do I integrate a replacement drive in the set?
RAID Utility 1.0 and SoftRAID do not seem to apply to 10.3.9.
Searched the knowledgebase but no joy.
Any and all help w/b appreciated.
Regards, Mike

Well, I've tried just about every combination of Terminal/diskUtil(TR), Disk Utility(DU), reboot, and mount/re-mount that I can think of.
But it always comes to this:
1 - after the mirror is apparently rebuilt (before reboot) - DU reports both drives as degraded and TR checkmirror reports both OK. (Next, Pick 2, 3, or 4 for next step
2 - then rebooting OS X, TR checkmirror reports slice 0 as OK and slice 1 0%, and DU immediately starts rebuilding disk1s3 (disk 1 slice 3 - see how drive formatting breaks down from TR list). wash, rinse, repeat - see 1 (Oddly TR checkmirror shows both disks OK shortly after rebuild begins but well before completion.)
3 - After reboot and starting DU, it starts rebuilding immediately with no chance to cancel, I initially forced DU to stop by turning off the bad drive (it crashed actually with no disk error msg). Restarting DU and selecting the bad drive before the mirror (good half) mounted allowed me to reinitialize the bad drive. Then, selecting the mounted mirror and dragging the re-inited drive to the RAID box, I was able to select rebiuld and try it again. (Note - in the raid box after dragging the initialized drive, the good drive's status was "Forming" - I have no idea whether this was good or bad.) wash, rinse, repeat - see 1.
4 - After rebooting and skipping DU, using TR repairmirror gave same results (again TR checkraid noted both drives OK before completion). I eventually learned to wait until the drive busy lights (red glow surrounding the power on lite when writing) stopped - a couple of more hours. wash, rinse, repeat - see 1.
At this point I'm out of ideas/procedures. I guess the next step is to try to delete the mirror set, re-init both drives (to zeros), remirror them, and copy backup folders to the mirror.
Some notes for Mac developers in case they peruse this forum:
1. Please provide a desktop message when the mirror mounts if the mirror is degraded or when it goes bad during operations. Also report which drive(s) is(are) the culprit(s).
2. Provide the serial numbers in the diskutil list output. Also provide which disks are participating in the mirror as well as their status.
3. Provide better documentation of terms and processes. For example, to stop forcing a DU crash, I figured out that if I turned off the good mirror drive so it wouldn't mount, the bad drive would mount (dimmed) but could then be selected for re-inititlization.
4. Provide a cancel button on DU rebuilding progress box and include a time remaining bar.
This is pretty basic stuff. If Xserve is to go big time, RAID needs to be more robust in operation, and much more friendly to repair.
I have no idea how long I was operating with my data unprotected.
Any and all ideas welcome.
Thanks, Mike

Degraded raid set now missing

I have or should I say had 2 250GB mirrored raid set. They would no longer boot I bought a new drive (same size) and attempted to rebuild the set. This went fine for a time but then failed. Now I can no longer see the raidset. I have tried booting from the server CD and it will stay booted just long enought to show me the raid set is gone or to open terminal then it shuts itself down.
I desperately need the data on this server. My most recent backup to tape was the end of January.
G5 Server Mac OS X (10.3.9)

Both hard drives were ruined by a power surge.

Offline Disc In Degraded Mirrored RAID Set

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