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

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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.

Raid 10 showing degraded, but both raid 0's are fine.

So 4 x 1TB black caviars.
2 sets of stripped, then mirrored together to make the raid 10.
Both stripped raid sets are fully online, just the raid 1, is showing up as degraded.
There is no rebuild option in disk utililty 13.
How do I go about via the terminal getting the raid 1 (a mirror of the stripped sets) to rebuild?

Also, Apple seems to call your setup RAID 0+1.
The bad news, as always, is that it appears you cannot just tell it to rebuild. You have to tear the array apart or add new blank drives, then you can rebuild it after that.
My experience with Apple Raids (now a bit dated) was that drives that had marginal blocks requiring too many retries cause a Mirrored array to become Degraded, sometimes dumping the drive that was too slow (or sometimes not). You may want to add at least one new drive and re-Zero [write Zeroes to get spares substituted] the one you replace, then prepare to do that again when/if it Degrades again. Keep careful track of what has been done to each drive!

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 1 becomes degraded?

I have (2) G-Tech 2TB drives set up as RAID 1 (mirrored). On the mirrored drive, I have numerous folders with assets for my edit, including a set of folders for FCP which includes a Capture Scratch folder. Initially P2 media was "log and transfered" into this folder within FCP. No problems.
But when I targeted this folder (G-Tech RAID>FCP>Capture Scratch) to capture additional video into, or even capture on another drive and then drag and drop into this same folder, the RAID set, in each occasion, became "degraded" (as indicated in Disk Utility) and is, for the second time. in the process of "rebuilding RAID slice", which takes 22 hours!
Any ideas as to why this is happening?
I am thinking that I should create a new folder outside my FCP Capture scratch and copy new assets into this folder instead?
I am using FCP6.02 QT7.4.5 DU10.5.6 MacOS10.4.11
Thanks in advance for your reply

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 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

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.

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

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.

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.

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

Why is my new 10TB Mirrored RAID array only showing 1.8TB total space?

I have 5ea. 2TB Western Digital hard drives in a FirmTek 5PM enclosure connected via eSATA to my Mac Pro (April 2007 model). Running Leopard 10.5.8.
I used Apple Disk Utility to set up a Mirrored Raid using MacOS Extended (Journaled) and have a check mark by "Automatically Rebuild Raid Mirror Sets." My Raid Block size is 128K.
So, by all accounts I should have more than the 1.8TB showing as available space on this array.
Here is how it looks in my Disk Utillity app (link to smug pic of Disk Uility window): http://richardbrackin.smugmug.com/Other/blogpics/RAID/754262625_iffPY-S.jpg
I found a site here: http://blog.scottmroberts.com/archives/15 that discusses removing a GPT header but that doesn't sound like a good idea.
How do I get more capacity? I have clearly done something wrong.

Oh, you have mirrored one drive with 4 others creating a single 2 TB array consisting of one main member and four mirrors. I doubt this is your intended result. If you want a 10 TB RAID, then you want a "striped" not a "mirrored" RAID.
Now, you can make a striped RAID of one pair of drives, another striped RAID with another pair, then create a mirrored RAID of the two RAIDs. This would give you a 4 TB mirrored array. But the only way to use all five drives in a single array is a 5 drive striped RAID. To learn more about RAIDs see:
RAID Basics
For basic definitions and discussion of what a RAID is and the different types of RAIDs see RAIDs. Additional discussions plus advantages and disadvantages of RAIDs and different RAID arrays see:
RAID Tutorial;
RAID Array and Server: Hardware and Service Comparison>.
Hardware or Software RAID?
RAID Hardware Vs RAID Software - What is your best option?
RAID is a method of combining multiple disk drives into a single entity in order to improve the overall performance and reliability of your system. The different options for combining the disks are referred to as RAID levels. There are several different levels of RAID available depending on the needs of your system. One of the options available to you is whether you should use a Hardware RAID solution or a Software RAID solution.
RAID Hardware is always a disk controller to which you can cable up the disk drives. RAID Software is a set of kernel modules coupled together with management utilities that implement RAID in Software and require no additional hardware.
Pros and cons
Software RAID is more flexible than Hardware RAID. Software RAID is also considerably less expensive. On the other hand, a Software RAID system requires more CPU cycles and power to run well than a comparable Hardware RAID System. Also, because Software RAID operates on a partition by partition basis where a number of individual disk partitions are grouped together as opposed to Hardware RAID systems which generally group together entire disk drives, Software RAID tends be slightly more complicated to run. This is because it has more available configurations and options. An added benefit to the slightly more expensive Hardware RAID solution is that many Hardware RAID systems incorporate features that are specialized for optimizing the performance of your system.
For more detailed information on the differences between Software RAID and Hardware RAID you may want to read: Hardware RAID vs. Software RAID: Which Implementation is Best for my Application?
Actually as I squinted at your tiny image I'm sure you never actually created a RAID. You have one 2 TB drives that are not properly arrayed with any of the other four drives.
Message was edited by: Kappy

Mirrored RAID not mounting/not showing as RAID (Disk Utility)

I have 2 Lacie Firewire Disks set up as a mirrored RAID (created by Disk Utility). I've been using this setup for about a year with no issues. But today I tried mounting the RAID and I got this msg twice (one for each drive)...
"Disk Insertion - The disk you inserted was not readable by this computer."
It then asks if I want to Initialize, Ignore or Eject. If I leave this msg up for a bit it eventually just goes away. But the disks never load.
I opened up Disk Utilities to check and see if the drives were listed and they are, but the RAID is NOT listed. All of the first aid options are greyed out. I tried to mount each disk but they will not mount, I assume because the RAID info has been lost?
Is there a way for me restore the RAID or at least get my info off of the drives? They contain a large photo library that cannot be replaced.
Powerbook G4 Aluminium 1.33gthz Mac OS X (10.4.7)

I never technically fixed the RAID. I used the program Data Rescue mentioned above to look at the drives and pull my data off of them. What I found was one of the drives was in perfect order, and the other drive had stopped recording data MONTHS ago. Basically the RAID became un-paired and stopped working correctly, and only one of the drives was saving the data. It freaked me out at first because the drive I decided to recover first was the one that was missing data. But I then looked at the 2nd drive and it had all my data on it, and I was able to recover it.
Anyway, Data Rescue worked perfectly. Now I just have the drives running independently. But I am staying away from the apple software RAIDs for now, as I did some reading and they seem to not be so trustworthy.
Also, Data Rescue takes quite a bit of time to pull all your data off, especially when you have a couple hundred gigs of data. Hopefully this helps.
Sam

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

Mirrored raid in early 2009 Mac Pro

I have created a mirrored RAID on Two 1 TB Hitachi internal hard drives in my Mac Pro running 10.8.4. I have put all of my working Photoshop files that used to reside on the desktop of my boot drive onto the RAID where they will stay until there is enough to move to them 1 TB backup drives that will be stored away.
Here's my question: This is the first RAID I have created in Dick Utility. The two hard drives show up on my desktop as one drive icon. Is this correct? Disk Utlity said that the RAID was successful, but how do I know the files I put on there have really been mirrored? I am attaching a screen grab of Disk Utility. Thanks.

Open Disk Utility and select ONLY the pseudo-physical Volume that is the RAID. In your case this looks to be "999.86 GB fotografia-LA Working Files RAID".
You will get a display similar to this one, which will give you a warm fuzzy feeling that all is well:
If either of the drives encounters a serious Error, the status changes to "Degraded".
Then the RAID must be rebuilt. One of the drives may have dropped out of the set, but occasionally it does not -- the set is degraded but both drives are still part of the set.
If you find yourself doing this rebuilding more than once or twice, Do not ignore such a call for help. It means a drive needs to be replaced with a new drive, not just rebuild the RAID again. When I had this happen to me, the errant drive needed twenty Bad Blocks spared out -- more than Disk Utility will do in one pass. It really needed to be removed from the RAID and set aside.

My mirrored RAID config shows degraded

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