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I have a MSI P35 Neo2-FIR Motherboard with ICH9R raid chipset. It's not a true hardware RAID solution, it requires software addon to work properly. There are drivers for Windows and dmraid/fakeraid for Linux.

I have 3 identical HDDs (ST3250410AS 250GB) for usage. I need 1 partition with data accessible from Windows and Linux (this one MUST be on RAID) and at least two for systems.

What disc/raid layout should I use? Protection of data (/home and "Document and Settings") is the most important

Zoredache
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Tomasz Tybulewicz
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2 Answers2

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If you only have 3 hard drives, your options are:

  • Two drives in a raid 1 mirror, plus one extra drive. You can use the extra drive for backup archives so that if you delete a file, you can restore it from the backup.
  • Two drives in a raid 0 stripe, plus one extra drive - the raid 0 will have no redundancy, so that's a dangerous option.
  • Three drives in a raid 0 stripe - no redundancy, so that's dangerous
  • Three drives in a raid 5 stripe - redundancy, but not too fast in terms of writes

If you could go up to 4 drives, then you can have one big raid 10 (or 0+1 stripe) that will give you fast reads/writes, plus redundancy across the whole thing. That'll make the most sense from an ease-of-management perspective.

The wikipedia article on RAID levels is actually quite good:

http://en.wikipedia.org/wiki/Redundant_array_of_independent_disks

Brent Ozar
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Important: Raid is not backup.

You set up raids to reduce the chances of needing the backup.

Mainboard raids increase your chances of needing a backup.

This in mind, your best bet probably is to set up software raid in the OSes. I seem to understand you are planning to have a multiboot environment. With multiboot, thats a pain, but I wouldnt trust anything important on a fakeraid managed by drivers on different OSes, if at all. Since the CPU will have to do the calculations anyway, there is no performance cost regarding fakeraid to LVM. Therefore, you must check performance in case you chose Raid 5. If 250 GB is enough, I would go for Raid 1 and use the third disk as backup.

Also try out failing the drives and such. Setup a boot / rescue disk so you can get at the data if your boot partition breaks.

Posipiet
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