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,

Similar Messages

Unbreakable Linux on a Stripe and Mirror Raid

Hi all
I was wondering if there is any best practice with respect to the placement of the Linux OS executables on Raid storage.
We have a 12 x 500gb disk storage unit and intend to stripe and mirror everything giving a total of 3 terrbytes.
I was considering placing the Linux executables on the raid along with the DB files etc and would be keen to know if anyone would anticipate any problems with this configuration.
Thanks in advance.
Cheers
Glyn.

Tom
Thanks for your reply.
Under normal circumstances I would also put the Unix OS on local drives.
However, as we will be running a number of Virtual servers spread over a couple of physical servers under the control of Virtual Iron, the Unix OS has to sit on the SAN.
I was wondering if perfformance of the Unix and Oracle executables sitting on the Striped and Mirrored disks would be bad enough to dictate that I should dedicate 2 out of the 12 disks as a mirrored pair for the Unix and Oracle executables.
Thanks for any further input.
Regards
Glyn.

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?

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

Got new miniMac servers with 2x750GB drives. How to setup and confirm RAID mirror?

Literally just got shiny new miniMac Server with the dual 70GB internakky hard drives/disks with
OS X 10.7.$ LION pre-installed. What a nice machine in a super cool box!
Seemed to bootup and run fine!
Now my issue (there will be more for this MAC newbie):
A. How to setup AND more importantly (item B below) CONFIRM that a RAID MIRROR is working?
Want nothing fancier than 2-nd drive is exact duplicate of 1-st drive at all times.
That is, an 'active and full up-to -the second" backup of the main 1-st drive.
I have done nothing to 1-st drive as it came from APPLE.
When I try to setup RAID set using DISK Utility, I get message about system(1-st drive) can't be used in a RAID or such.
yet I can add 2-nd drive to what I tink is a RAID set and then 'Enable' it.
It seems to add another entry to thr left-side of drves list panel but not sure that 1-st and 2-nd drives are BOTH in the new
"RAID SET' or that the set just consists of the "single" 2-nd disk?
B. I don't think that 1-st drive data is actually being duplicated to 2-nd drive.
For instance, how do I know that it was 'caught up' to match 1-st drive AND then is
staying caught up?
C. A 'RAID UTILITY' Icon brings up a not-available message, but I think that is because I don't
have HARDWARE RAID controller, just software RAID, correct?
D. What is 'Time Machine' and how does it play into this? I do assume that somehow/someway I need to
have off-machine backups also to be truly protected? How would a 2-nd identical miniMAC server be best
deployed to back each other up, in addition to their own internal RAID-ed disks that items above address?
My whole point of buying 2x750GB disks was to have mirror RAID set and
(foolishly) assumed that factory would set it up that way.
Please help me get setup right so when the inevitable crash happens,
I have some chance of recovering from it.
Regards,
Paul T
emai: [email protected]
Apple ID: N3UD
Phone: 610-613-0610

A. What are you adding to the RAID: a partition or a hard drive? You can only add hard drives to a RAID. RAID Utility should confirm that your RAID is working
B. No, I don't think so
C. It's because you haven't got RAID hardware.
D. Time Machine is a backup system in external drives. If you want, you can do backups in a external hard drive.

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.

Splitting Mirrored Raid Drives

Hello,
I have two external drives that are striped with one mirroring the other. I want to split or separate them without losing data. Can I just continue using the primary drive that comes up on the desktop (without plugging in the mirrored drive) without any problem? If I separate the mirrored drive, I presume I will need to erase it, and will not be able to access the media on it, correct? Is there any way to access the media on it and use it without erasing media?
I tried to access just the mirrored drive to see if it showed up in Disk Utility, which it did not. Then, after plugging in both drives, Disk Utility is now repairing raid slices...for another 8 hours. Did I damage my media?
If one can never access the data on a mirrored drive, then what is the benefit of it being a "backup"??
Thank you in advance,
Video Editor

Is the RAID striped or mirrored. You said they were "striped" with one "mirroring" the other, but this is incorrect terminology. Either the RAID is striped or mirrored. You can create a mirrored RAID from two identical striped RAIDs, but an individual array is either striped or mirrored.
If you truly had a mirrored RAID, then separating the drives would not affect the data as each drive simply has a copy of the other. However, if you truly had a striped array that you separated, then your data may be lost completely because each drive actually has one half of the data and the other drive has the other half. Each file is literally split between each drive. Lose a drive and you lose the data.

Numer of hard drives and what raid to use?

I am currently trying to figure out what setup to go with when I order a Mac Pro, most things are pretty straight forward but I have a question in the Raid/HD setup, I would like to use 4HD's, 2 250g's for OS and applications in Raid 0(striped) and 2 750g's for data/file storage in Raid 1(mirrored), would I need the Raid card, or does the motherboard Raid cover that, would I set it up as two separate Raid utilities, Raid 0, and Raid 1, or does Raid 0+1 cover that, any feedback would be greatly appreciated, thank you in advance.

Software RAID will do what you want. if you want to get fancy then invest in a Highpoint RAID6 or something.

What's the best way to upgrade a mirrored RAID drive?

I have two 3TB Firewire 800 drives which are almost full which I'd like to upgrade. The drives are configured as striped drives using the Apple (OS-X) RAID utility in disk utility. Is it possible to configure three drives as RAID 5, or four drives as RAID 10, or am I better off just going for a couple of larger drives and staying with the striped configuration? The drive is mainly used for an iTunes library, iMovie content and Aperture vaults so speed isn't that critical.
Thanks in advance

You can convert to a striped RAID but not without erasing the drives. The only ways to make a larger mirrored RAID are:
Buy two more identical drives. Make two sets of Striped RAIDs which in turn can be configured into one mirrored RAID by mirroring the two striped RAIDs.
Buy two larger drives, configure as a mirrored RAID, copy the data from the old RAID to the new one, or have two mirrored RAIDs.
Regardless of what you do you may end up erasing the data from the present setup if it involves breaking the RAID. If you break a mirrored RAID the data on each drive will remain intact until you re-use the drives in some other manner such as converting the mirrored RAID to a striped RAID.

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

Possible to boot B&W G3 from mirrored RAID??

Hi all,
I've tried to get my B&W, running server 10.3.9, to boot from a mirrored RAID (RAID 1). So far, I can successfully create the RAID, run the software installer, and choose the RAID with Startup Disk, but upon restart, it doesn't recognize a valid system (flashing system folder/question mark).
There's a tech article that states the B&W G3 won't boot from a striped RAID (RAID 0), but I've not been able to find anything definitive regarding mirrored RAID. Does anyone know for sure (or know where I can find documentation)?
TIA,
Brad
B&W G3 Mac OS X (10.3.9) 10.3.9 server

Thanks for the info. I had no problem either creating the RAID (successfully in both Disk Utility and Terminal), installing the OS, or selecting the RAID pair as the startup disk. I'm doing this with ATA disks.
Once done, though, the system won't boot from the RAID pair. I know that the B&W open firmware won't allow startup from striped RAID (technical article http://docs.info.apple.com/article.html?artnum=58258 applies), but don't know if this applies to mirrored RAID as well.
Has anyone out there successfully booted a B&W G3 from a RAID 1 configuration?

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.

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.

Striped and Mirror Raid

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