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Being familiar with the software raid modes and dynamic disks from the server versions, I was wondering if there is a document or even just common crowd knowledge that indicated what software raid support was available for each version of Windows 7.

Also - all the various raid levels supported for booting or just a data recovery mechanism (e.g. you can connect three RAID-5 dynamic disks to an already booted system).

I would prefer to stay away from modified/copied DLL's from the server variants, as well - please note - this is Windows software RAID - not fake-raid from your BIOS or an add-on card.

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5 Answers 5

up vote 16 down vote accepted
+100

The Professional/Enterprise/Ultimate editions of Windows 7 officially support the following dynamic disk modes:

  • Simple
  • Spanned
  • Striped (RAID-0)
  • Mirrored (RAID-1)

These are the officially supported modes. It has been possible in previous Windows releases to enable unsupported modes through DLL modifications and/or registry changes, and this will probably be the case in Windows 7 as well. At your own risk, of course.

RAID-5 dynamic disks are only available in Windows Server editions.

Note that dynamic disks are not available in the Standard/Home editions of Windows 7.

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Is there documentation to reference this against? Also, does support include booting from those different dynamic volume types? –  Goyuix Jul 31 '09 at 23:30
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I fired up Windows 7 Ultimate RC in VirtualBox and I was able to create a RAID1 mirror and boot from it. After adding three more drives I was able to verify that I could create spanned and striped volumes as well - though I did not have a chance to try and create them then reinstall on that newly created volume for attempting to boot - though honestly booting isn't that interesting from those types. I also tried the RAID5 support and it is greyed out in the GUI and DISKPART told me it was not available with this version of windows. Accepting this answer. –  Goyuix Aug 1 '09 at 1:17
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I had some more time so I created a striped volume in Win7, then shutdown and detached the original virtual HD leaving only the two drives in the striped volume. Booting off the the Win7 ISO gave me a notice I needed to format the two drives because "The partition contains one or more dynamic volumes that are not supported for installation." –  Goyuix Aug 1 '09 at 3:42
    
According to blogs.withalan.com/a-few-notes-on-windows-7-software-raid Home version would be able to Span/Concatenate. –  anttir Feb 24 '12 at 12:54

It's a bit late now, but here's a screenshot in Windows 7 Ultimate:

Windows 7 disk management

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Umm, RAID offered by the bios isn't the best but is far better than raid provided by the operating system. RAID provided by a proper controller such as one that has an abundant amount of cache which can be configured (if protected by an onboard battery) exclusively for write cache are the better option and should not be regarded as "fake". This is why expensive controllers which offload resources from the operating system to calculate parity can provide the best performance and redundancy including the classic mirror (RAID 1) for the o\s with a dedicated or global hot spare and either a raid5\6\10 or 50 depending on the type of data you have. Generally you will separate different i\o patterns to separate logical volumes for performance i.e. sequential read and or write generally will go to a raid 1 as would be the case for transaction logs in say an SQL server and random i\o patterns should be kept - not only for disaster recovery, but for performance on a separate logical volume of say based on your disk size as this affects the rebuild rate, to either a raid5\6\10 or 50.

Hardware raid is always the best option, that is why controllers can cost several thousand to tens of thousands of dollars depending mainly on the amount of onboard cache and options such as migration from say raid 1 to raid 5 or 6... it really doesn't compare to "fake" software raid.

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5  
Most mobos use a JMicron controller to offer RAID. This "fake" hardware RAID still does the calculations on the main CPU but only works with that specific controller; change your motherboard and you lose the array. Software RAID is much better than this fakeRAID. –  Mircea Chirea Aug 24 '10 at 14:56

http://www.alanjlee.com/interesting-bits/a-few-notes-on-windows-7-software-raid/

  • RAID0 (striped) - confirmed under Windows 7 build 7100
  • RAID1 (mirror) - confirmed under Windows 7 build 7100
  • RAID5 - not confirmed - the option is visible but greyed out, even with 5x disks in Windows 7 build 7100
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I think you have your RAID0 and RAID1 backwarwds. RAID1 is mirror. Also, does it supporting booting from a software RAID volumee? –  Goyuix Jul 18 '09 at 19:27
    
goyuix: I am just quoting the article :) –  TheTXI Jul 18 '09 at 19:43
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Why are you quoting an article that is clearly wrong? RAID0 is striping: en.wikipedia.org/wiki/Standard_RAID_levels#RAID_0 RAID1 is mirroring: en.wikipedia.org/wiki/Standard_RAID_levels#RAID_1 –  asjo Jul 25 '09 at 18:03
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Because like most people do, we assume Wikipedia is correct and we're only trying to be helpful by quoting it –  Ivo Flipse Jul 30 '09 at 11:08
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@iconiK, but @asjo was ;-) –  Ivo Flipse Aug 24 '10 at 20:10

The software raid option has been a part of windows since NT 4.0. You can do RAID 0, RAID 1 and RAID 5.

Also remember that Windows now supports linking in directories like unix now.

RAID O requires at least two disks. RAID 1 requires at least two disks. RAID 5 requires at least three disks to work.

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This is misleading. Windows XP did not do software RAID5, though there were a number of sites (for example, windowsreference.com/windows-xp/…) that showed you how. –  ChrisInEdmonton Jul 29 '09 at 22:06
    
You needed to use SCSI disks for it to work. At least every time I set it up it was on UUW SCSI drives. –  Axxmasterr Jul 30 '09 at 0:22
    
You should be able to use any fixed (non removable) disk fro RAID under windows. I currently have a SATA drive and a PATA drive acting as a RAID0 (stripped) volume on which I have my games installed. MS generally includes R0 and R1 in all editions apart from those explicitly marked as "home" with the addition of R5 in "server" and "datacentre" editions. You can hack XP to allow RAID5, but it isn't supported and could be broken by the next patch you download so isn't recommended. –  David Spillett Jul 31 '09 at 21:11

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