Mirrored raid and bootcamp.

On my mac i have a mirrored raid of 2 external hdds for music and photos etc.
I intend on buying a new mac soon, now I know I can just unplug and plug them into the new one no problem.
My question is though, that with my new mac i will be using bootcamp, and I am unsure what will happen if I boot into windows with my mirrored raid setup still plugged in.
Jonny

I'm going to try to install XP using an extra drive I have lying around and the Pro Caddy:
http://www.transintl.com/store/category.cfm?Category=2704
These keeps the 4 main drive bays free for OSX.

Similar Messages

Concatenated RAID and Bootcamp

Anyway to access a mac formatted concatenated RAID in windows 7 under bootcamp? MacDrive does not seem to support this.
Thanks

Hi Fred,
http://support.mediafour.com/entries/170484-macdrive-compatibility-with-raid-dri ve-arrays - so your assumption is correct.
To my knowledge there is (currently ?) no other way to access an OSX-raid from BootCamp Windows.
Sorry
Stefan

Xserve 10.5 RAID and partitions

I am trying to configure my two 750G harddrives to be mirrored RAID and partition them, but am getting no love from Disk Utility.
I have tried partitioning one and then making them RAID. I have tried making them RAID and then partitioning.
If I partition both and then try to RAID the two equal partitions, only the first pair show up.
I'm a bit of a newby, but did the RAID and partitioning before in 10.4.11, but that was a few years ago, and I don't think it works the same in 10.5.8.
Any help will be greatly appreciated

hi,
once I had the partitioning as I wanted (options -> GUID, right?) I chose my volume A1 in disk utility, selected RAID, added A1 (stupid GUI) and B1, adjusted the raid level and let it do its thing. Same for A2 and B2. This worked for me: I have a 10.5 and a 10.6 install and can switch between the two.
Does this help?
cheers,
Michael.

RAID 1 (mirroring), cloning and booting...

After recently buying a new dual quad-core, I wanted to expand the hard drive space a bit, and enhance the security of a part of the data. Having a 500G disk in bay 1, I planned on putting one additional 500G to create a mirror with the original one, and two more disks simply for space (500G and 1T). I soon encountered some problems..
As I don't have a RAID card installed, I would have to use Apple's software RAID from within Disk Util; but I soon discovered I would need to initialize both disks that were to be in the RAID (is there a reason for this? I expected I could create a clone drive, so a mirror with one in the RAID already present...). Well, this would mean I have to backup all my data first, then boot from another disk (like the Leopard install disk), create the RAID and replace all my data... So here are my current problems:
- my Mac Pro won't boot from the Leopard install disk (it's an original Universal disk, so that shouldn't be it); it won't boot from other external disks either, but I believe that's caused by the partition tables being in APM, not GUID, as they were created on a G4...
- I need to make a complete clone of the boot disk, but all I can do with Disk Util (or CCC) is make a clone of the Mac partition (or loose partitions at all). I have a BootCamp partition as well, which I would like to clone too, so what I'd want is a possibility to clone the whole drive, instead of independent partitions. It seems there is a terminal command able to do something like that, but I'm not familiar with using it.
- I read about the software RAID solutions causing problems in Leopard (corruption of RAID headers). Does anyone know more about this, and whether it has been solved?
I'm sorry for putting three things together, but I thought it might make it easier to understand if the connection between the problems was clear. Any help would be greatly appreciated.
Piotr / iBear

Hmm.. This does explain a few things, especially the part about having X.5.2 as a minimum.. The slight problem with the the disk that was packaged with the machine is that my dad (for whom I'm setting it up) has been "cleaning up" his disks - I've had a hard time finding the Leopard disk for that matter... - and is now on a trip for the next two weeks. I'm now configuring a new external install - entirely fresh and updated to X.5.4 - to try booting from that.
I thought both AppleRAID and SoftRAID had that problem, that's what I understood from the post you left in another topic, but I guess I don't have to worry about that anymore. happy
The purchases have actually already been made, and as there were no 640G disks available, I had taken the 500G's. So, the machine is already set up with 3x500G (2xWD, 1xSeagate) and 1x1T (Seagate as well). As the original system is on one of the WD's, I wanted to create the RAID with two identical disks; will it make any difference if they are not? (I know it will work, but would it have any impact?)
And just a last small question: as I noticed before, CCC doesn't do entire drives. Should I partition the RAID drive like the original and then use CCC to copy the BootCamp partition? (found SD after a small search) > I think the same questions go for that as well...
Many thanks for the very fast reply!

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

Fan Speeds, and Mirror Raid with New Internal Hard Drive

Regards,
I recently installed and formatted a new hard drive in my PowerMac dual 2.3 ghz computer and I have a few questions.
1. Now that there are two hard drives do I need to do anything to ensure that the fan on my computer can keep them cool? I think the fans I have in the hard drive bay is enough, but I do not know if they will automatically set themselves to run properly. I can monitor the fan speeds and temp from iStat pro, but do not remember what level the temperature was before installing the new one.
2. Given that my new drive is a SeaDisc hard drive and the older one is a Western Digital, will this cause any problems in creating a mirrored RAID. I believe that both are 7200rpm drives, and my second hard drive is a little larger (I will just have unused space after making the RAID). I am concerned with the fact that these two drives are from two different manufactures. Will this cause problems or drastically slow down the reading and writing of data? Has anyone else experienced problems in making a mirrored RAID from two hard drives that are not exact matches, and even come from different manufacturers?
Any advice will help.
Thanks
earpshmael

Hi earpshmael;
Generally when creating RAID arrays the more similar the drive the less problems you tend to have.
The real question is exactly why do you want or need RAID?
I think so many people seem to think that RAID will solve all of their problem. I hate to tell you the bad news but it will not.
Generally there are to varieties of RAID available using the software RAID built into OS X which are 0 and 1. RAID 0 or stripling is generally for moving large file rapidly for applications like HD video. It usually doesn't help the OS. RAID 1 or mirroring is for protection from drive failure. It is not a valid backup solution.
Allan

XServe and Mirrored RAID drives

I wonder if anyone can help me. An XServe of ours went down. It looks like it is the Logicboard. I have taken the system drive out and put it into a G5 machine and the OS opens fine. I took one of the RAID drives which were mirrored and put it into the second slot in the G5. The problem is that the drive did not have any of the files for the last 6 months. Then I removed that drive and put in the other RAID mirrored drive, and this drive had all the files on. I am a bit confused. If the drives were mirrored shouldn't the drives both have the same content on? Also if I change any of the files on that RAID mirrored drive will that affect the way the RAID is set up when I put the drives back in the XServe when my logicboard gets replaced?

Does that mean that RAID mirrored drives don't necessarily have the same files on? What is the point of calling it mirrored then. Also this makes no sense. Because isn't the point that if the one drive fails, you have an exact mirror of the drive to recover your files. How does this help, if a drive fails, and the other mirrored drive is missing files from the last 4 months. Luckily we have external drives connected to the XServe which daily backup the RAID drives on the XServe. But imagine if you didnt have this, and one of the drives failed.
If I had to reformatt the drives and then reinstall the data, would this possibly correct the weird issue with the RAID drives not being exactly mirrored?

Striped and Mirror Raid

Having moved my boot drive to the lower optical bay I was thinking of setting up two WD 2TB Black Caviars as a Raid I Mirror.
The other two drives are Seagate 7200.11 which I thought I would use as a Striped Raid.
In doing this am I likely to have issues with reliabilty or performance using Disk Utility to create these two Raid's.
Thanks
David

Those 7200.11's were the ones with bad firmware, are rather old by now... and while might be of use...
http://www.bing.com/search?q=7200.11+firmware
#1 max out RAM and use 64-bit kernel
#2 scratch would do better with the 2TB Blacks (and setup an outer partition of 1/2)
#3 I'd rather see two backup sets and methods: clone your data also instead of a mirror which uses up an internal drive bay
yes it use to be common and helpful to have a stripe for media files, for scratch, and for saves (moving files you work on to scratch array is fine but just be sure to save elsewhere). Adobe was slow on saving large 2 GB files so an array helped.
Some use SSD for scratch. Or PCIe SSD products (up to 1TB).
http://www.macperformanceguide.com - blog and check the Articles link.
http://macperformanceguide.com/
http://eshop.macsales.com/shop/SSD/PCIe/OWC/Mercury_Accelsior/RAID
Apple mirror arrays have been limited to being slow single-threaded I/O but yes you can have a mirror and stripe, and even on the same pair of drives - and as long as not trying to read/write concurrently because otherwise you would throw the drive iinto head-contention scenerio.
When to use mirror:
http://macperformanceguide.com/Backup-mirror.html
And some would just stripe all 4 (identical only) drives.
For $800 you can: use 4 x 10K WD VelociRaptors 550MB/s / 2 x 4TB Hitachi 350MB/s / 2 x 240GB SSD
SSDs and you get into needing more bandwidth and SATA3 6G controller.
Or upgrade to 32GB RAM
A combiination of more RAM, SSDs, and two more WD 2TB Blacks,

Win7 Pro not seeing Mirrored Raid

I have 4 hard drives in my MacPro.
disk 1 OS X 10.6 (500GB)
disk 2 Win 7 x64 (300GB) set up through bootcamp
disk 3 1TB storage
disk 4 1TB storage
Using Mac's disk utility, I made the two 1TB disks a mirrored RAID. I then checked to see if I could access the new RAID set under Win7. Win7 does not see them accept under Disk Management where they show up as hardware, but they have no drive letter. In short, I can't see them as usable drives or the mirrored RAID I set them up to be on the Mac side.
As a test, I went back to the MAC side, deleted the RAID set which then unlinked the drives making them show up on the MAC desktop as two separate drives instead of one. Rebooting to the Win7 HD, I noticed that now windows sees the two drives as usable storage.
Now, this is not what I want. I want a mirrored RAID usable by both the MAC and Win7.
*How do I get Win7 to see the mirrored Raid?*

Hi Arminya,
most likely you are out of luck.
Windwos 7 can not see/use harddisks that use Mac OS Extended (Journaled) as file system.
And the only solution furll read/writte access from Windows is MacDrive and they don't support software RAID through Disk Utility http://assist.mediafour.com/index.php?a=knowledgebase&_j=questiondetails&_i=123&nav=%26gt%3B+%3Cahref%3D%27index.php%3F_a%3Dknowledgebase%26_j%3Dsubcat%26i%3D1%27%3EMacDrive%3C%2Fa%3E
Sorry
Stefan

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.

General HELP for RAID and HOME NETWORK... I'm a bit lost :(

First off, I'm sorry about the long post but I just wanted to ask everything at once since I don't know what effects what?
Over the past years I've had a MBP and have always added Western Digital Mybook drives whenever I needed storage. One of clicked and died this past year and I lost some data since I was "MANUALLY" backing up. Since then I've tried to read about RAID, NAS, and DROBO type devices.
I recently bought a Mac Pro 2008 edition because I needed more speed. I mainly edit wedding photos in Lightroom but also come from a heavy motion graphics background and do some After Effects projects from time to time.
Here's a list of my current setup and what I'm hoping to achieve but I'm in over my head of what to do???
1 Mac Pro (2008 edition) - I'm considering setting up 4 1TB harddrives inside that are mirrored. I was looking at the Caviar Black or Hitachi drives...
2. I have two Airport Extreme Base Stations for my home network. (One is plugged into my Mac Pro and the other is near my Vizio LCD and Xbox 360. I've been toying around with sharing iPhoto slideshows (which I really like the idea of) The problem is that it seems really slow for video and hiccups on the stills sometimes. It doesn't seem to make a difference if it's pulling it from the Mac Pro or from a USB drive attached directly to my Airport Extreme. How do I speed this up? Is it always going to be faster to stream from the Mac Pro over ethernet cable than a harddrive plugged in through USB?
3. A few RAID and NAS solutions I've been looking at are the following but I don't really understand what I get with an external device vs an internal? I also don't know which is BETTER? for easy reliable backup.
http://firmtek.stores.yahoo.net/sata5pm2se2.html
http://www.dlink.com/products/?sec=0&pid=667
http://www.qnap.com/prodetail_feature.asp?pid=110
http://eshop.macsales.com/shop/hard-.../RAID/Desktop/
http://www.synology.com/enu/products/CS407/index.php
4. I've been reading mixed reviews about the Drobo but don't quite understand if it's a better solution then setting up a mirror INSIDE my Mac Pro. I DO NOT want to buy a $900 raid card for the Mac Pro though. Do most people choose the Drobo because they only have laptops? Should I only consider building something inside my Mac Pro?
5. I was considering Chonosync for backing up 3rd level backups
6. I just bought a Blu-Ray drive for 4th level backups that I can send off site.
7. I have all these other Mybooks. Two of them are mirrored but only one is a 1TBx2 Sata drive. The rest are IDE. I guess I'll just use these for misc things? Maybe just plug one into the Xbox for watching movies?
8. My neighbor down the hall has a similar setup and is using a Mac Mini to stream things (through Front Row) like Hulu and videos another room to his TV. Mine doesn't seem to stream fast enough. Since I have the MBP that I will use rarely since I got my desktop I was considering using that instead of Apple TV or a Mac Mini but it's too slow? Maybe I set it up wrong?
PLEASE HELP? I don't know what I'm doing.

A few RAID and NAS solutions I've been looking at are the following but I don't really understand what I get with an external device vs an internal? I also don't know which is BETTER? for easy reliable backup.
Hi,
For backup, video work, photography and expanding the Mac Pro storage capability the FirmTek SeriTek/5PM would be my choice. The bundle that you pointed to will work if 130MB/sec. is fastest enogh for your needs. The card is only $70 in the bundle which makes it a nice deal.
http://firmtek.stores.yahoo.net/sata5pm2se2.html
If you want 200MB/sec, performance I would go with the Sonnet Tempo E4P or the HighPoint RR 2314 if you desire RAID 5 redundancy.
http://www.amug.org/amug-web/html/amug/reviews/articles/sonnet/mac-pro/
http://www.amug.org/amug-web/html/amug/reviews/articles/highpoint/2314/
Trying to use NAS via the network will be 3-7x slower than the SeriTek/5PM. The SeriTek/5PM is a much better choice for backup, video and photography. NAS is good for low energy, always on, low use server needs. However, you can simply turn Mac OS X file sharing on and the Mac Pro will provide performance faster than any NAS.
Drobo - Why do people even consider this option?
The performance is USB speed even with a FW800 connection.
Users have reported losing data with firmware updates.
And the unit is one of the most expensive, slow performing options available. I cannot image ever wanting a Drobo
Backup Software:
I like SuperDuper. I also like using the "Restore" tab in Disk Utility to clone one disk to another. The key to good backup is to keep it simple and regular.
MyBook - NOT
If your storage needs exceed more than a single FireWire backup disk you really need to go with eSATA. The SeriTek/5PM and the Mac Pro combination provides virtually unlimited storage capabilities as the tray system allows new hard disk sets to be easily loaded or dismounted.
Have fun!

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

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

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

Recovering data from a damaged mirrored RAID

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

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

Advice on RAID and backup of new server in CAD office

Hi, I work for an architects firm and we're looking to purchase a new server.
Our current situation:
• Dozen workstations running Leopard, on a gigabit network
• Server running Leopard Server (Standard setup), with one 250GB ATA hard drive (17GB space spare)
• Data files are backed up and taken off site each day with a triple rotation of external hard drives, using Retrospect.
• The server hard drive is cloned to an external drive each week, which stays on site, using SuperDuper.
• User accounts from workstations are all backed up to an external drive, which also stays on site, using Retrospect.
• And I've been trialing Time Machine, backing up the data to an external hard drive, but I can't see this replacing Restrospect backup as Time Machine doesn't compress the files.
To the future:
• What sort of RAID setup should we go for in a new Mac Pro server?
• I'd like to throw it all into performance but I'm thinking we should probably use a RAID to replace our SuperDuper clone from above.
• When you have mirrored drives presumably if one fails the other one just carries on doing all the work by itself?
• Should we run the system on two mirrored drives and the data on the other two? Or if I'm looking for more performance would I be better having 3 mirrored drives for the data and one for the system? Is this even possible?
• Is it possible to get the smaller 73GB SAS drives for the Mac Pros? It seems you can only get the 300GB ones, which are £500 a pop!

Keep in mind that mirrored RAIDs require two similar drives preferably the same make and model. A mirrored RAID only provides drive failure protection, it does not provide data redundancy. If you need a backup then you need two mirrored RAIDs using one to backup the other. This is also true of striped RAIDs which only provide increased storage but provide no protection against drive failure nor provide data redundancy.
These factors should be taken into account when planning your setup.
Personally, I would not recommend using Time Machine. Aside from being fairly basic as a backup utility it is not sufficiently reliable in my opinion for your situation. Retrospect is a much better choice.

Failed Mirrored RAID - How to determine which disk?

Hello Apple Support,
I've run into a bit of trouble with my RAID and I was hoping I might find some help with it. Here's the deal:
I have two 1.5 TB Seagate Barracuda drives in an OWC Mercury Elite AL-Pro enclosure. I recently noticed that one of the disks has failed, so I need to yank it outta there and send in on back to Amazon to get a replacement. However this has proved a bit tricky, for a number of reasons.
1. I initially noticed that one of the drives had failed because the available disk space was grossely outta wack, Finder reported that there were 921 GBs of free space, when there should only have been about 300 GBs. Along with this, many of the files I'd recently downloaded were missing, although older files were available. I thought this was strange because the RAID is mirrored, which (I thought) meant that both drives contained the same data, so that if one failed the other drive would still have the current data.
2. I opened up the OWC enclosure and disconnected one of the drives and then booted up the RAID to see if I'd be able to determine by "guess and check" which drive had failed. Now, however, I get this picture from Disk Utility:
When I now navigate to the RAID volume in Finder, it shows me the 900 GB of freespace. Does this mean that the drive I did not disconnect is the failed drive?
Beyond this, how do I go about restoring the RAID when I receive the new drive back in the mail?

If you start with 5 x 2TB disks in raid 3 or 5, you will have a net space of (5 - 1) x 2TB = 8TB.
When you later add a 6-th or 7-th disk, by expanding the array, you will increase storage by 2 TB for each added disk.
At the same time you will increase the transfer speed of the array.
Expanding an array is not difficult, just time consuming, especially for a raid5, because all the data need to be rewritten to all the disks, but also the parity needs to be recalculated and written to all member disks because of the distributed parity in raid5. Raid3 has the advantage of writing parity only to a single dedicated disk.
I suggest you only use identical disks in the array. If you now buy 5 identical ones and at a later date decide to add more disks, make sure the new disks are identical to the ones you now use.

Mirrored raid and bootcamp.

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