Degraded RAID set (mirror)

I am running a pair of 2 GB external drives in RAID 1 (mirroring) using the OSX Disk Utility. Recently I noticed that the set shows it's RAID status as Degraded and one of the two drives is indicated as "Missing," which keeps the "rebuild raid set" button grey. However, I can verify each of them separately and they appear to be okay. Only one of the drives appears to be partitioned correctly; the "missing" drive simply shows a RAID slice for the entire 2 GB.
I would recreate the mirror set, except that I don't have anywhere to store the 1.3 GB still on the good drive, and I believe I cannot create the set again without erasing the contents. (I back up to the RAID set as well as use it for un-backed up storage, which I think is safe as long as the RAID set is working.)
Any ideas how to get the "missing drive" to reappear, so the system can rebuild the set? Or any other ideas to get out of this problem? Thanks.

It doesn't change the problem, but obviously I meant TB (not GB)

Similar Messages

Degraded RAID set help

Hello Support Community,
I have a 4 bay RAID set that all of a sudden is showing as degraded. I have two pairs of disks each striped, and then have those two pairs mirrored. Not sure if this is a correct RAID format, but it is what it is right now. So both striped sets say online, with no problems, but my mirrored set of those two pairs shows that it is degraded. See below.
Any thoughts as to what might be happening? I have the options set to automatically rebuild the RAID. How do I know this is happening? How long should I expect this to take? It's a 4TB raid in it's current config, and there is about 3.7TB of data on this RAID. I have everything backed up in two other locations. Am I better off starting from scratch? Or should I just let this thing run for 2 weeks and see what happens? Any help would be greatly appreciated.
Thanks
Dave

No, I was doing all of this in disk utility. I left the arrary running overnight, and it's back online now. Not sure what got screwed up.
Thanks

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.

Degraded RAID set

Hi All,
Dual Core 2.0 running 10.4.2. I set up a raid set and one of the drives almost immediately reported a SMART failure. So I replaced it. No problem, no downtime, even. The machine functioned fine with just the one drive.
Now...
Bought a replacement second drive. Added it to the RAID set, rebuilt it. No problem, but the RAID set still reports as degraded. I cannot delete the damaged drive because I don't have it anymore (hindsight is 20/20). How can I delete the non-existent drive?
Thanks,
Danny
Dualcore 2.0 G5 Mac OS X (10.4.2)

Yeah, but if you've only got 2 slices and one of them
is out to lunch, well, it's not rocket science to
know what your risk is ...
Well, actually, one failed and has been replaced. It was pretty easy to add the new drive to the RAID set (just drag and drop into the RAID and then rebuild it). The machine worked ave without the failed drive hence...
What worries me is that I don't know for sure
if the RAID array is actually working as designed and
I haven't found a definitive statement about what
exactly 'degraded status' means. Does it mean
'not working as well as it should but still doing the
job' or does it mean 'this RAID array isn't doing
diddly and sometime soon you're gonna be up the
creek.'
As you could see, the RAID was working very well. One drive died and the machine continued working fine, so there was NO downtime (except to switch off the G5 and yank out the failed drive). I'm guessing degraded means that one of the registered slices is missing. But if you have another registered slice, then you're fine.
More specifically, if my primary drive actually does
die, is there a complete dupe on the second drive in
the array or not?
As in my example, that's exactly right. The hard drives are exact copies.
I guess I should go ahead and do a hard backup on an
external drive and then just pull out the primary
drive (it's hot-swappable) and see what happens.
Yes, RAID is not back-up. If you have a corrupted directory structure due to software, then you would have to rely on a back-up. But it's nice to have both, really, as the most common problem with disks is hardware failure and this minimizes problems involved.
To tell you the truth, though, I'm not sure I'd bother again. I find that using psync (available from bombich.com under the Carbon Copy cloner section) works fine. It creates a fully working system disk and can be set to clone the start-up drive daily. If the main disk fails, most people won't even notice that they're starting up from the second one.
So back to the question: how to remove this degraded status?

Problem Rebuilding RAID set with 10.5?

I have 1 RAID set (mirrored with autorebuild) composed of 2 (identical) HD. I got a message in 10.5 Disk Utility that one disk had failed and that the set was degraded.
I replaced the drive and I am getting an error message during the rebuild "Unrecognized filesystem".
I can still see and access my RAID set (1 slice still ok) so minimal damage here but I don't understand why I am getting this error message when trying to rebuild.
Any idea?
Thanks
setup:
-mirrored raid set
- autorebuild selected
- 2 slices (160Gb, GUI, OS journaled ext)

Hi VK2CPJ,
Today ( I slept on this idea was exhausted from previous day) tried on two blank eide drives in a raid box, no raid built just two independent drives, one set for master the other slave. A couple of observations:
I did not raid because I want one small partition to contain a Leopard boot install from the DVD. The message I received from disk utility was that if I restore that DVD my raid may be unusable(if I did raid). So I did not raid the drives but let them stand as master and slave. I wanted to do a APM on the small "boot" partition to see if my intel and PPC Mac would in fact boot from that restored Leopard DVD boot partition. I used start up pane on both PPC and intel and they would not boot up from that Leopard partition even though the start up pane showed the disk as a startup device. Using the option key booted both Macs. Now I'm not sure if doing this was to procedure because the Apple docs says to use a PPC Mac to do this process. Which I have a difficult time to understand. I'm assuming that the doc says that because APM would be default and assisting the user not to make any option mistake. So currently I'm trying this same procedure using a PPC Mac to test out whether start up pane will boot both Macs. I don't think it will but do think using option within the start up manager will work. If so then does this mean imply that the start up pane has a bug or that user does not require a PPC Mac to do the setup process. Let you know shortly.

Rebuilding RAID set takes 2 hrs?

Don't know if this is the right place for my post ...
I have a 160gb Raid set (mirrored, 2 disk 160gb each), automatic rebuild). One disk failed, showing degraded in Disk Utility. After replacing the failed HD with a new one disk utility started to rebuild but it took 2hrs...... Is this normal.
I don't have any experience with RAID set and was wondering if this was normal.
Thanks
F
10.5.1
Powermac G5.
2 160GB external HD mounted as RAID mirrored (Mac OS X journaled extented)

Yes, that's normal -or, at least, not unusual.

Repairing RAID set takes a long time?

I have a 160gb Raid set (mirrored, 2 disk 160gb each), automatic rebuild). One disk failed, showing degraded in Disk Utility. After replacing the failed HD with a new one disk utility started to rebuild but it took 2hrs...... Is this normal.
I don't have any experience with RAID set and was wondering if this was normal.
Thanks
F
10.5.1
Powermac G5.
2 160GB external HD mounted as RAID mirrored (Mac OS X journaled extented)

Yes, It has to copy the entire master disk to the new slave disk plus keeping track of all changes to the master disk at the same time. It will go faster if no applications are running during the copy.

Suggestion for fixing broken raid set

Jesus. Again. Twice in 6 months. Raid set failure.
2:58pm today : Drive 3:50014ee2aede46eb missing - Previous drive status was inuse
2:59pm today : Degraded RAID set RS1
2:59pm today : Degraded RAID set RS1 - No spare available for rebuild
Jesus...
After launching the Raid Utility, I notice that one drive is actually missing from the drive bays.. Its just gone, and I have not done anything to it. This happened last December as well. Hard booting the drive (pull out, push back in) worked last time to get the drive online, but jesus. Twice? I should maybe replace the drive? I am using Apple Raid Card, people say it turns to be pretty strict about the drives state, but why the **** it keeps disappearing from the system?!
I was already on the phone with one Apple consultant about this, and I think everything is pretty OK. I have good backups, and gladly, the OS RAID set is ok. Only our accounts and work files were in there, and all is secured. But this is really stressful.. Feels like I can't trust these drives one bit. And they are good drives, standard hardware what comes with Mac Pro.
Just when I was starting to think that everything is finally working smoothly..
Any recommendations about how to act now. I know what I have to do but, it would be encouraging if I would get some steps to how to fix it. Working order etc.
Everything works tho, taking one separate set of backups at the moment just in case. I just need to get my act together and fix it. God I am annoyed tho.
Good weekend to everyone tho. Comments are appreciated.

Yeah, I already ordered a new drive.
I can't do any tests for the bad drive cos it just disappeared from the system totally. I guess it could come online if I hard boot it again (like when the raid set broke last december), but I don't feel like doing it before I get the new drive. Need to analyze it on another computer.
The consultant I talked with earlier mentioned that the RAID card is pretty strict about the condition of the drive. But I would like to know if that is why the drive keeps disappearing, if it really totally ejects it from the system . I heard that some cases the the Raid Utility just shows the red light what indicates the drive state if there is a problem, but for me the drive is just gone totally.
Hope that the new drive arrives soon. Will the Raid rebuild itself if I insert the new drive and mark it as global spare ? That's what I understood from reading the Raid Utility manual.

Need help with RAID Card and degraded Raid-5 errors

Dear all,
I recently purchased a used Apple RAID card for my 2008 Mac Pro 8-Core. The installation went smooth, the card was immediately recognized and the battery reconditioned within one night.
So I started setting up a Raid Set with the 4 identical drives which I already used before as a software Raid. But each time the Raid Level-5 Volume is created, somewhat later the status turns red and the Raid is listed as "degraded"!
A closer look at log reveals:
+19:42:54 Drive carrier 00:01 inserted+
+19:42:27 Background task aborted: Task=Init,Scope=DRVGRP,Group=RS1+
+19:42:27 Degraded RAID set RS1 - No spare available for rebuild+
+19:42:26 Degraded RAID set RS1+
+19:42:22 Drive carrier 00:01 removed+
+15:10:57 Created volume “R1V1” on RAID set “RS1”+
So it seems that the drive from Bay 1 somehow gets lost (removed) a few hours after the volume is being created and anysoon later it's being "reinserted"...
Of course, the drive is NOT removed, nobody touched the Mac Pro! Also I did the same procedure 3 times and the result was always the same.
I also tried setting up JBOD and different RAID levels which do all work without a problem. Only when choosing RAID5 (what I intentionally bought the card for), the problem reappears
Anyone any solution or hint for me concerning this problem? Many thanks in advance!

One drive completely broke down later. Replaced that drive and since the problem's gone!

Why a Apple RAID controller card cannot delete a RAID set?

Hi,
I just have a problem with my RAID set created with RAID Utility. My configuration is as follows:
     Mac Pro (early 2009 model) 2 x 2.66GHx Quad-Core, 16GB DDR3 1066Mhz Memory
     Apple RAID Card (HW Ver 2.00 and FW Ver E-1.3.20)
     1 x 1TB HD (Apple original) in Bay 1 as boot disk configured as Enhanced JBOD
     3 x 2TB HD (WD black series RE) in Bay 2 to Bay 4 configured as RAID 5
     Mac OS 10.7.4
The RAID Utility showed the following messages:
Degraded RAID set RS2 - No spare available for rebuild
Degraded RAID set RS2 - No spare available for rebuild
Degraded RAID set RS2
Drive 3:50014ee20352f5e8 missing - Previous drive status was inuse
Drive 3:50014ee20352f5e8 failure detected - Primary disk port unusable, previous drive status was inuse
Furthermore, RAID Utility shows:
1) Bay 1 (RS1 boot drive): Assigned, verified, Status good. viable (good)
2) Bay 2 (RS2 RAID 5): Assigned, verified, Status good, viable (degraded)
3) Bay 3 (RS2 RAID 5): Roaming, verified, Status good
4) Bay 4 (RS2 RAID 5): Assigned, verified, Status good, viable (degraded)
It also showed "Severe Events" message: "Degraded RAID set RS2 - No spare available for rebuild."
I tried to delete the RAID set using Apple RAID Utility but nothing happened. Can anyone help as I have to rebuild the RAID set from scratch? Thanks.

Hi flognoth,
flognoth wrote:
I have swapped the drives in bays and it is always bay 2. I'm coming to the conclusion that either the RAID card is failing in bay 2 or there is a Lion / Mountain Lion issue with the RAID card.
I would say this is not "a Lion / Mountain Lion issue with the RAID card", as I have an "Early 2009 Mac Pro" that is running Snow Leopard (10.6.8), fully patched, that is exhibiting a similar issue, after about 4 years of no such problems.
My RAID configuration is just like yours: 4x 2TB drives, with Bays 1 & 2 as RAID 1 and Bays 3 & 4 also as RAID 1. I keep losing either Bay 1 or Bay 2 disk, and after reboot typically see it as a good disk, in the green, but now unassigned to a RAID set, and marked as "Roaming". When I assign it as a spare, so far the RS1 RAID Set begins to rebuild, and things are okay for a short while.
Initially this happened about once a month, starting about 3 months ago, now it is a weekly or several times weekly event.
I've put in new disks (several), restored from a Time Machine backup, and just came in today to find the Bay 2 disk "Roaming".....
I'm going to try a new Mac Pro RAID card, as I have a spare - just looking for information about whether the replacement RAID card will pick up the RAID sets from info cached on the disks (I hope!), or whether I have to newly create the RAID Sets & Volumes, and then re-populate from Time Machine / the old disks.
I will say that I've been running 8 "Early 2008 Mac Pro" computers with RAID cards, each configured as above, and 4 "Early 2009 Mac Pro" computers similarly configured. These were all deployed between late 2008 and the beginning of 2010. I've had little difficulty with them, and they've been wonderful when an actual disk failure has occurred. I've had about 6 actual disk failures among all these setups.
cheers!

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.

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

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

Degraded RAID set (mirror)

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