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How to Create a Software RAID Array in Windows 7

Instead of having a bunch of separate drives to deal with, why not put them together into one big drive? You can use software RAID to accomplish this, and here’s how to do it.

Windows has built in functionality to set up a software RAID (Redundant Array of Inexpensive Disks) without any additional tools. This makes it easy to turn your existing spare hard drives into massive storage or even redundant backups. In this example we are going to set up a spanned disk that takes three 2 GB disks and creates one 6 GB disk using Windows 7 Professional.

Editor’s Note: For the example in the article, we’re showing how to create a spanned drive, which isn’t technically RAID, but it works similarly and creating a RAID array is exactly the same—you can choose your preferred RAID option from the context menu.

Image by carlosgomez

Set Up Your Disks

The first step you need to do is backup your information on the disks you want to use in the RAID. While it is not required that you format your disks for some of the RAID options, don’t take the chance and make a backup.

Once all of your information is backed up, open your start menu, right click on computer and open manage.

When computer management opens click on disk management on the left side. Any disk you want included in your RAID you need to delete them from the top area of disk management.

Once they are deleted you should only be left with disks you do not want included in the RAID. The other disks will still be there but they will show up in the lower pane and show their spaces as unallocated.

Create Your RAID

In Windows they don’t call their RAID options by the traditional 0, 1, 5, 10 etc. Instead they use spanned, striped, and mirrored as the options for creating software RAIDs.

Note: RAID-5, although one of the options, isn’t actually available in Windows 7 due to licensing issues. Thanks to the commenters for pointing that out.

A spanned volume will create a single partition that will literally span all of the included disks whereas a striped volume will deliberately break up files across multiple disks in an attempt to improve read and write performance. In both cases there is no redundancy so you need to create your own backups.

A mirrored volume and RAID 5 both have some redundancy but you lose storage space to create the parity files needed for recovery. For this example we are going to go with the simplest volume type and create a spanned volume even though it isn’t technically RAID.

Right click on the first disk you want included in your RAID and select new spanned volume.

This will open up the New Spanned Volume Wizard in Windows. Click next and then select which disks you want included in your new volume (a.k.a. software RAID).

Assign the new volume a mount letter or mount point.

Name and format the volume and click next.

The final step just reviews all of your settings before the disks are formatted and the new volume is mounted.

You should also receive a warning letting you know that if your operating system is on one of these volumes you won’t be able to use it because the volume is now a dynamic volume instead of a logical volume.

Finally the disks will be formatted and once the drive is mounted you should be welcomed with the familiar AutoPlay prompt.

If you browse to Windows explorer you should also see that the new volume has the combined storage space of the three individual disks used to create it.

Justin is a Linux and HTPC enthusiast who loves to try new projects. He isn't scared of bricking a cell phone in the name of freedom.

  • Published 11/29/10

Comments (43)

  1. echelon

    There should be a guide following this to be able to recover files when one drive in a RAID Array goes kaput.

  2. Lady Fitzgerald

    I fail to see the advantage to a spanned RAID array. You may gain some speed but at what cost? One drive goes down, the whole shebang goes down. Back ups would be challenging because you would have to back up everything at once, probably to another RAID array.

  3. ColdEmbrace

    Great article but no matter what I read I still can’t understand what a RAID array is. Any chance you could clear that up for me?

  4. The Geek

    In retrospect, showing a spanned RAID as the example was probably confusing, but the setup for all of them is the same—you can just choose a different option from the menu when you’re prompted to choose between Spanned, Striped, Mirrored, etc.

  5. asdf-chan

    @ColdEmbrace

    Raid gives you functions to use your harddrives for specific problems. There are a lot of Raid options but there are just a few that are used normaly like Raid 0, 1, 5, 6, 10 or 01. If you want to have copies of your files on a hdd you could simply copy stuff from a to b, which is pain in the ass, because everytime you change data you must change it on the drive where your backup-copies are too. So there is this method called mirroring. You tell your software or hardware to mirror the content from one disk to another, so everything is done by hard- or software. The simplest mirror-raid is 1, you just need 2 drives and that’s it. So if your harddisk somehow f**ks up, you still have the other one.

    If you don’t care about backup disks, you might want something more performant. An option would be raid 0, with a method called striping. Striping does nothing more than fusing 2 drives to 1, simple math 1TB+1TB=2TB. The thing is, if you use striping those disks are no longer independent. If you write data the soft- or hardware desides to split those drives to little spaces, so called block. So if you search for your stuff on 2 harddisks, it would take a while to find the data you wanted (sequential search), if you use striping the search action would be performed parallel, which is way more faster. But if one of those disks f**ks up you are done. There is a simple chance of restore data that was stored with this raid, depends on the block-size.

    Raid 10 is mirroring and then striping (Raid 1 and 0) and Raid 01 is backwards. 5 and 6 are a bit more complex but

    If i made a mistake, correct me

  6. Bikram

    Err, this might not be related to this topic, but I’m anyway posting my problem here as I see ‘Dynamic Disk’ mentioned towards the end of the post.

    In my old PC, I had two HDDs. But somehow one of them became ‘Dynamic’ and ever since, it is not showing up in explorer. :( I can see it in Disk Manager but not in explorer. And I’m finding no way of reverting it back to ‘Logical Disk’ without formatting it. Can you help in this matter.

    Please delete this comment if it is ‘non-topic’ here.

  7. Peter

    “In both cases there is no redundancy so you need to create your own backups.”

    Even in any other case, including having redundancy in your disk array, you need to create backups.

    Redundancy does not protect you from data errors/incidends, like deleted files or crashed partitions/volumes, e.g. by a software bug, a virus, or accidentally.

    You always need to have backups. Always. Current. Always. Backups. Always. Backups are not Redundancy. Always make backups. Redundancy is not backup. Always make backups. Have the backups ready. Know how to use them. Ensure, that they work. Backups. Always. Current. Always. Working. Backups. You get it.

  8. Kellan

    I’m assuming that “Redundant Array of Inexpensive Disks” was a joke.

  9. Tom

    @ Kellan – What makes you say that?

  10. Iktwo

    If I do this, it won’t show in other OS rigth? I mean some linux? do I have to do it there too?

  11. mmg1818

    wtf is this ?

    only bios have RAID

  12. User1001

    @Kellan: Inexpensive or Independant… Most people say independant…
    @lktwo: This is software RAID managed by Windows 7. No you wont see your RAID array in other OS. And dont make a RAID array in the other OS on the same disks, you most likely will overwrite your Windows RAID and lose everything that was on this array in Windows…
    @mmg1818: Nope. Some BIOS have RAID, many softwares allow to manage RAID, lots of hardware do RAID, etc. The best is Hardware RAID. But Windows 7 does allow you to have a nice basic setup with preferably Mirror RAID… But yeah as stated before, you need backups anyway!!! RAID does not prevent corruption to propagate to both disks in a mirror, so you end up with a nice mirrored data corruption… ;)

  13. Mike

    ok this is a valid alternative to use old drives, but they were removed for a purpose – old, slow and outdated. – honestly do you really want to deal with this issue if ONE drive goes bad the entire array fails?

    go buy yourself a TB external HD with fast spin up – would work better than this solution

    old drives are good for one purpose – disassemble and sell to other office workers as mirrors for their cubes!

  14. Adam

    @mmg1818, you are actually incorrect.

    Also I think the article should have pointed out that RAID 5 is not available in Windows 7.

  15. RichC

    Very cool. If I use a mirrored volume across 2 USB hard drives and later plug the two drives into another computer, will the new computer recognize the raid setup?

  16. Ray

    which site is available for downloading old western movies for free like bandidos,return of sabbata etc

  17. Iktwo

    Thanks @User1001 so, if I do this in stripped mode, I wouldn’t be able to use those partitions on other OS..

  18. User1001

    @RichC: This is software RAID… Your software (Windows) must know about the configuration… So NO, you wont be able to plug your USB drives in another computer and see your RAID… Especially not in stripped mode.
    @lktwo: No prob. And you’re right, you wont see the array in another OS. You software must be aware of the situation. The other OS would not be aware so it will see 2 physical hard drives.
    @Mike: Totally right. I would not stripe old disks… (2GB disks, really??? Direct to trash!)
    Buy 2 x 2TB hard drives at 100$ each. Plug in Windows 7. Mirror RAID. You end up with redundant data, nice speed (2010 disks!) and no more 1990 hard drive noises!!! ;)
    If your data is of any value to you, dont put it on a stripped 1990 disks array!!!

  19. Justin Garrison

    @Mike The screenshots were actually taken with a VM, I just created the 2gb disks to show how it works.

    @Peter so very true.

  20. Quink

    I have one hard drive (C:) with all my data and OS, another identical new one that is blank. Can I make a RAID 0 (mirror) without reformatting the C drive? I noticed that little note at the end of the above instructions that says “Finally the disks will be formatted …” I am using Windows 7 Home Premuim.

  21. John

    Peter: “You always need to have backups. Always. Current. Always. Backups.”

    I’d add to that “At least one backup offsite. Always.” Because you never know if your onsite backup may become unavailable, whether due to fire, theft, a lightening hit, or hardware failure. Carbonite is cheap at $50/yr, or backup to an external drive and take it to a trusted spot (e.g., safe deposit box, family or friend’s house).

  22. Deck Hazen

    Interesting topic! — I still prefer a hardware solution – let me throw in my 2 (or maybe 3) cents:

    http://www.hazen.co.nz/06_raid5/06_index.html

    — Deck

  23. Jon

    @Kellan – No the name RAID means exactly that “Redundant Array of Inexpensive Disks” is the long name for RAID.
    In my experience and I mean I’ve used all levels of RAID from 0 – 5 and the new one, the only one that actually worked very well was RAID 5. I usually setup RAID 5 as 4 or more drives with “Hot Spares”. These are drives that will step in in the event of a drive failure of the main RAID drives, so as an example 4 or 5 drives in the setup means 3 will be used for the day-to-day working and 1 or 2 drives sits idle. When a drive fails 1 of the 2 drives will become active until the failed drive is replaced. Once replaced, the new drive will usually rebuild the data that was lost. Now some system (mostly those using a Hardware RAID card) will do this automatically), some you have to control via the software.
    How does this work in Windows 7?

  24. Steph

    From Wiki: RAID, an acronym for Redundant Array of Independent Disks (formerly Redundant Array of Inexpensive Disks). Independant… Today all disks are inexpensive… ;)

  25. Farooq

    this information is too good………………………………………

  26. john

    I fooled around with this a few months ago. I have 4 2TB drives for movie storage. 4tb for the movies and 4 tb for the backups.

    I used the “Mirroring” feature within win7 disk management. For the most part it worked ok, however it always seemed to be “resyncing” all the time. I also didn’t like the idea that if I accidentally deleted something, it would also delete in the backup drive.

    I have been using puresync for a couple months now. I run it every 2 weeks or so. Quick, easy, free.

    I am thinking of spanning the 2 drives together but, like one user said before, what happens when 1 of the drives go bad? Also, if I want to un-span them, does it delete data? Too much risk with too valuable info.

  27. b0be

    @Jon, a slight correction. RAID-5 is uses n+1 drives plus a spare. So if you have 5 1TB drives, 4 will be active and the fifth waiting to be used if one of the four goes down. This gives a data capacity of 3TB. There is 1TB of parity data spread around (very precisely) across the 4 drives so if one dies, the data on it can be reconstructed from the other three. When one dies then a background operation recreates the the data of the dead drive and writes it to the spare. When that process is finished, the remaining 2 drives and the “spare” are again a fully redundant RAID-5 set. When the dead drive is replaced, it becomes the spare. In some implementations the “spare” is copied back to the new drive and then becomes the spare again, in others the new drive just hangs around as the spare.

  28. Chris

    This is just JBOD, though, because this implies no parity, data security, etc.. lose one volume, and goodbye to data on all.

  29. Jon

    I had no idea that they finally added this to Windows with W7. It’s about time!

    Can you set these up at installation?

  30. Ralph

    With Windows7, rather than a RAID setup for a home PC, I use a 2TB drive, from a HDD dock and create a disc image once a week or so. I create an image anytime I make any major changes. The SATA disc prices have dropped to an economical level that makes it an inexpensive alternitive. If the main drive crashes, just run the recovery disc and put the image back on the new drive. This minimizes data loss without taxing the power supply and other resources of your main system.

  31. Doss

    hmm sounds good, but not professional, the whole point of raid is that if os goes down, you still will be able to recover your data… but with this configuration if os dies, also raid dies with it. so ???? it is just me, or i think that this does not make sense.

  32. Aravinda

    Im using a 1.5 speed asrock mothrboard,with 512ram(DDR1 model).I cn run wndows7 well in ma pc.Bt the prblm is i cnt install da sound drivers.Is there an any way to get my sound to use wndws7?Help me.

  33. DiamondDrake

    in your article you said the acronym for RAID stands for “(Redundant Array of Inexpensive Disks)” This is NOT RIGHT. the I stands for Independent. I certainly hope this is a typo. Either way you should fix it. That’s embarrassing.

  34. Benjamin

    Is this necessary for large HDD e.g. (320GB)

  35. b0be

    Inexpensive / Independent

    Back in the last century, in the 1980′s when RAID was invented by Patterson, Gibson and Katz, commercial drives were expensive slow and low capacity. About then the first SCSI (Small Computer System Interconnect) drives started coming out at a reduced price and initially it was believed that they were much less reliable. RAID made it possible to improve their reliability. So initially it was RA Inexpensive D. Soon enough the big old disks got left behind, and the small disks quality improved and the name became RA Independent D.

  36. Steven Pace

    This is how a Raid Array works.
    If you have a chain of disks (any length, from 2 to infinity)
    Each disk has different information in it, and is the same size, except the last in the chain, the one used for redundancy. The Redundancy disk contains the “total” of all of the rest. It is calculated by taking the exclusive OR of all of the rest. So if any one disk fails, the rest of the chain can be used to reproduce ALL of the data on the missing disk. Rather than having to have a backup of each disk, you can protect against the failure of ANY of the disks in the chain. If two disks fails at once, you loose everything, but this is such an unlikely event, it can safely be ignored. Of course the striping is also a benefit; it effectively makes the transfere rate the total of the transfere rates of all of the drives added together. Of course 2 GB drives are worthless, but marginally useful drives can be usefully employed this way.

  37. BigB

    Ok, one point that could be argued about is Intel’s creating of the Intel Matrix Storage Technology, which allows you to create, at the BIOS level (or rather a ROM chip that runs as port of the boot process) these RAID arrays. Most relatively new ones all have RAID 0, 1, 5, and 10.

    The beauty of the “matrix” part of the technology is that you can create different array levels on the same disk set, something not commonly available on the standard old RAID cards that have been around for years… it was one type of RAID on a disk set, and that’s it.

    So this argument can be defeated by that, somewhat. How? Let me use my setup as the example: I have four 1TB WD black’s in my box. I have created a 50GB partition for the OS, and set it to be a RAID 0 (spanned/striped) for pure speed on the read/writes, cause I want the system partition to be able to read and write as fast as possible. The remnants of the space on the drives, I have set to RAID 5. I get one shot on the system partition (1 drive fails, system partition is failed)… but I can have a disk fail and still have the RAID 5 array intact, albeit slower until the drive is replaced and rebuilt.

    But — here’s the catch — how simple is it to set up a nightly imaging job for my C: /system partition… the backup 50 gigs to either the RAID 5 or an external HD. in the event of a single disk failure, I can boot up using the Windows 7 restore CD, and restore an image backup (once the drive is replaced) or I can do a parallel boot from a VHD if I want, restore the image, blah blah.

    Point is, you can have your cake and eat it too. There’s several ways I could go about repairing the computer in a drive failure disaster using different types.

    Even better would have been this idea — RAID 10 is superior to 0, 1, and 5. Why?

    1- it has the read speed benefit of RAID 0, if only two disks are read in tandem. technically, 4 disks could be read in tandem, but i don’t think it does that. regardless, it is missing the risk of RAID 0 (1 drive fails, you’re gone)…. the speed is not missing as it would from RAID 1 (single disk to read from, has to do double writes) or RAID 5 (read speed is good, but write speed is slower because of parity calculations, plus you lose 1 drive’s worth to that parity info)… RAID 10′s downfall comes in a major and minor point — RAID 10, you half the amount of storage/hd’s you buy… and that sucks from a “bang for your buck” perspective. nobody loves buying four 1TB hard drives and only getting 2TB of usable space. even the loss of -1 drive in RAID 5 stings a bit… but in the end, it’s about asking these questions:

    how important is speed to me? how vital is my data, and am i backing it up in any other way or simply relying on the RAID array? is my data worth the cost/loss of 1 or 2+ drives in the name of sound sleep?

    the best solution, IMO are TWO independent arrays. use a RAID 0 for your OS partition, and image that sucker religiously to an external HD or other array, then decide what the rest of the space is going to be used for. if it’s gonna be temp space for editing movies and graphic design, etc… then you dont need redundancy.

    on the same hand, if you’re just storing/archiving your media like mp3s and movies… speed is not a real factor. you’re not going to be able to listen to mp3′s faster because they’re stored on a RAID 0, c’mon. for archival/backup purposes, RAID1 is best… RAID 5 is acceptable (but not really necessary), and RAID 10 is top notch.

    think of it this way, visually… in a raid 10, you combine striping and mirroring… so your data written across the drives would look like this:

    -1 -2
    AB CD

    -3 -4
    AB CD

    there’s your four disks. if drive 1 died, drive 3 takes over, and you’re still OK. if the world is against you that day and you have a second drive fail… pray that it’s either 2 or 4, cause you’ll still have a complete set of the data (AB+CD). if disk 3 is the lucky one to fail in this scenario… you’s screwed. BUT… as mentioned… as the number of disks in the array increases, so does the chance that any one of those drives will fail. with 2, you’ve got 2x the chance of a disk failure. three disks, 3x the chance, etc (actual real life percentages aren’t so clear cut, but that just illustrates the point).

    so in closing, think of it this way:
    RAID 0 – get the full usage of disk space, you get the fastest read and write speeds of all the mentioned arrays, but you also get the highest chance of catastrophic data loss.
    RAID 1 – you’re going to lose typically 1 hard drive to the mirrored copy, but you have a realtime backup of your data, you have 1/2 the chance of losing data, vs. the 2x chance in RAID 0. that’s four times the risk difference between the two.
    RAID 5 – you’re obviously looking for some sort of protection/redundancy in case of a drive failure. you’re going to lose a drive to RAID 1, so the drive cost is equal for RAID 5 as RAID 1. both of these you can lose one disk.

    and here is the main decision point between 1 and 5 — is speed important? you’re going to take a small write speed hit and possibly CPU cost (depending if the raid controller has a dedicated chip to do parity operations to offload the processor)… 5 can get you greater read speed than 1 will. write speed is fairly negligiable difference.

    but remember — if and when a raid 5 fails (vs. raid 1) — you have to acquire a new replacement drive… quickly. then you have to rebuild the array. depending on circumstances that can take from a few hours to a few days. that’s a scary window where a second drive could take a dump and you lose it all regardless. whereas, in raid 1, the “extra” drive has been there since the beginning, so you don’t have to worry about the rush as much, cause that 2nd working HD takes over instantly. the second drive still needs to be replaced, but there isn’t really as tedious of a “rebuild”… it’s merely a drive to drive copy, which takes significantly less time.

    here’s an even better idea to trump the sata raid deal altogether… how about instead of spending 3-4 hundred dollars creating a raid 5 or 10 array, get yourself a nice solid state drive for your OS partition, then use the other disks as your main data disks for archival, where speed won’t matter.

    that’s way too much of a diatribe for me to go on an already written article, but I hope i contributed some sort of valuable info that maybe was missed somewhere or helped someone to understand the concepts better… sorry for the long post!

  38. Steve

    Still no RAID 10 in WIN7? I am building a Hi Performance Digital Audio Workbench. I really need the high performance afforded by RAID 0 and the data protection of RAID 1. Nobody has mentioned anything about RAID 10 set up for WIN7. The Mobo (ASUS) only provides RAID info up to Vista. Any way to do this with the OS installed?

  39. Mark

    The thing is both spanned volume (JBOD) and stripped volume (RAID 0) doesn’t offer any fault tolerance but what the stripped volume offers is double the original performance while spanned volume doesn’t give any performance boost.

    So basically there is zero reason to opt for spanned volume. If you want performance boost, go for stripped volume or if you want data redundancy, go for mirrored volume.

  40. Sheporama

    This was very helpful, Justin, despite all the blah blah from the wanna-be nerdo wags who commented off topic … and there are a lot (get your own blogs).

  41. Vaughan Risher

    BigB – Your comment was awesome (I’ve copied and pasted it into a text document so I can refer to it later)! And thanks for the in depth article as well – there are still alot of people out there who need to read it.

    I’ve been running windows on a “fake RAID” 0 (motherboard on board controller driven) for more than a year now and backing my data up on an external drive. Now that I’ve been planning a new computer build this week, I’ve been doing research about what route to take this time around, and have learned in the process that “fake RAID” is not the way to go for a few reasons – the main one being that given any failure of your motherboard, the array setup would not be able to be read unless a computer with the same fake RAID controller was found – the other being that the software RAID (the one created by windows in this case) is pretty much just as fast. The only real disadvantage of using a software RAID is that you cannot use it to boot windows. To anyone who might ask – “won’t that slow my computer down”? The answer is – not any more than a motherboard’s “fake RAID” controller would, because in that case, it’s STILL the controller’s software driver that’s doing the RAID work. So, essentially, by using that fake RAID, you are creating an array that’s only advantage is that you can boot windows with it. Creating a true hardware RAID will remove the burden from your CPU, but the boards to do this typically cost more than $300 a piece.

    My solution to this issue is to put windows on a non-raided SSD and create a windows based software RAID for your remaining drives.

    I hope I’ve added a little tidbit of newly acquired information to your mind’s internal RAID storage solution and good luck to anyone out there who might be trying to make the same decisions as I have!

  42. Asher

    Big B. Your comments were highly helpful.. made the options a lot more clearer for me.. Thanks to your diatribe :)

    @Sheporama – Isn’t it with comments that we help out each other in blogs and discuss the blog itself

  43. pol098

    I posted this elsewhere, will copy as this is a long-running thread that people may find:
    I’ve been using Windows RAID for a long time, RAID 1 mirrored non-boot drives under Win XP (patched for RAID) and Win 7. Works fine, drives have failed with no down-time, also unplug from XP, plug into Win 7, ready to go. If the machine is powered down without shutting down, it always resynchs – I think Windows is worse in this respect than it could be, too cautious, but adds chance of data loss if a drive fails while resynching. The purpose of this post: I had a lot of resynchs, and it always resynched after sleep or hibernation. I am using SATA drives; they were set in BIOS to IDE emulation mode. I changed to AHCI, and it’s MUCH better, never resynchs after sleep. (If you change an installed system from IDE emulation to AHCI, you need a registry patch BEFORE BIOS change to make Windows recognise drive, otherwise machine won’t boot – Google this if you don’t know what I mean). Windows will load its own AHCI drivers (in my case drives clicked constantly, though not faulty) – replace them with the AHCI drivers for your motherboard. Don’t know if this is general or just my (AMD) setup. HTH

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