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Does software RAID 1 (mirroring) in Windows 7 improve read speeds?

I'd like to set up RAID 1 to help protect my important documents (yes, yes, I know it's not a backup), but performance is also important to me. As I understand it, RAID 1 should theoretically be able to improve my read speeds by n times, where n is the number of disks.

Is Windows 7 able to get this boost? I haven't been able to find out this information anywhere.

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Depends on the raid controller and model of hard discs what actual performance increase you will experience. Too many variables to give a correct answer. –  Moab Jan 2 '11 at 19:37
@Moab: I think he said software RAID. –  oKtosiTe Jan 2 '11 at 19:52
That he did. he also said Raid 1, mirror will have absolutely no increase in speed, I think he has it confused with Raid 0 –  Moab Jan 2 '11 at 20:12
I have hardware raid 1, it only reads from one drive, is it different for software raid? –  Moab Jan 2 '11 at 20:22
Raid1 can potentially improve READ speeds as each disk is read from in turn in much the same way as a striped array, remember, at this point the same data already exists on both disks. Writing data takes longer than normal as it has to duplicate the effort by writing the same data to both disks. The question refers to reading data. Since he only has one drive, he will not see any improvement at all. –  Tog Jan 2 '11 at 20:42

2 Answers 2

up vote 12 down vote accepted

I think this blog answers it best. It shows actual speed tests for raid 0 and raid 1 between a single disk, windows software raid, hardware raid, and fake raid.


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Thanks. That's very helpful. –  Rich May 30 '11 at 1:27

Yes, theoretically it will increase the speed by n, because all n drives can access the same file at the same time. If you have 10 painters painting a room, theoretically, the work will go 10x faster than with one painter.

In reality, however, these 10 painters don't know how to work together. There's a ton of painting over and their styles don't match etc. Same with RAID1. Few operating systems have drivers that can utilize the benefits of RAID1 (I believe BSD may be the only remotely major one).

Conclusion: No, the software hasn't caught up yet. If you want speed and protection, you're better off buying one better drive than getting two crap drives, and perhaps investing in MozyHome.

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