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i recently start working in a new (small) company having an "old" file server with windows server 2003 and an hw raid 5 with four disks. Last week the server is dead. We decided to build up a newer system with windows server 2008 using a PC with this hardware : CPU: Core i3 3,2 GHz RAM: 2GB Motherboard supports Raid. (we can't use the hw controller from the first server)

Examining the disk configuration i not sure about which one could be better for us between a Radi 5 with 4 disks (as in the past) for OS and Data, or two distinct Raid 1 (one for the OS and one for the Data).

We have about 60 users and about 10%-15% of them could concurrently access the server.

Moreover, in these scenario it is better an hardware raid controller or the "fake" onboard raid could be enough.

Thanks.

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3 Answers 3

RAID 1 (mirroring) is just a simple duplication of your data, it won't increase any performance

RAID 0 will definitely increases ur performance since it stores half of your data on one drive and half on the other, but it is more vulnerable to data loss. If any one drive fails, then ur data is lost.

RAID 5 is somewhat a combination of these 2 things. By using 3 drives it can store half of your data on one drive, the other half on the second drive , thus enabling it to read/write faster, and then it uses the third drive for redundancy. If you lose any of the 3 drives, your data can still be recovered.

RAID 5 is the best possible solution, for ensuring both data availability and improved performance.

If you go with an onboard RAID Controller, then you will be using your processor to do a software RAID which is very time consuming and the more drives/total storage you have, the longer it takes. So RAID 5 is not advisable in such a scenario.

If you are going to use a dedicated hardware based RAID Controller , then you can go with RAID 5, Else RAID 0/1 is the suggested solution.

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This answer has multiple problems. First, RAID1 can improve read performance, as it can read the data from multiple disks, thus striping reads, but not writes. Second, RAID5 is not advisable at all anymore, as the chance that you have an URE during recovery is just too high. Use RAID6 in this case, instead. Third, with modern system speeds, a software RAID (not chipset fake RAID) isn't necessarily much slower than a dedicated controller - in many cases, there is no noticable difference for the users. Fourth: Rebuild time depends mainly on the size of a single disk, not the amount of disks. –  SvW Oct 17 '12 at 8:10
    
This is true for RAID 1, RAID10 and RAID6 and on both software and hardware controllers. Lastly, as I said that software RAID isn't too slow compared to hardware anymore, I wouldn't rule out a software RAID6, depending on your use case. –  SvW Oct 17 '12 at 8:14
    
thanks for your replies. I know that there's a great discussion about which could be better between sw and hw raid implementation. Now i came out with another issue (i'm a little bit confused) : when motherboard bios has a raid option that should be used if one wants to use the onboard controller or a thirdy hw controller? Should it be setup even for pure software raid implementation? –  Liuc Oct 17 '12 at 8:47
    
Coming back to my first question my thought was : maybe two raid1 are more reliable than one raid5. if one of the disks (one per each raid) fails i can mount another one, and all should work. Moreover i can move the data raid disks to another pc (if compatibility is allowed). Am i wrong? –  Liuc Oct 17 '12 at 8:59
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@user141438: Never, ever use the chipset RAID for anything. These things are evil (as in unreliable, difficult to handle, opaque, incompatible with other mainboards ...). Either use a dedicated hardware RAID or the software RAID option offered by the OS. These days, I'll say the same about a RAID5: Don't use it. Period. –  SvW Oct 17 '12 at 9:09

Instead of two raid 1 you could build one Raid 1+0, which gives you speed advances over raid1!

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Bad idea; it's better to split off your OS and data arrays where possible. –  HopelessN00b Oct 17 '12 at 9:35
    
Can you expand on this a little @user582846 –  Iain Oct 17 '12 at 10:48

Using Windows, the built-in software RAID is often both much faster and more reliable unless you buy truly enterprise-grade hardware RAID-adapters.

As SwenW wrote, chipset RAID should not be a part of the equation at all, when buying small business-grade motherboards always get those without such options.

Always separate the operating system volumes from data volumes onto separate physical spindles. Your two mirrors suggestion is the most obvious and appropriate.

  1. Two mirrors
    • Mirror 1: OS
    • Mirror 2: Data
  2. Add cheap/small OS disks
    • 2 cheap 60GB SSD mirror (~50 bucks a piece at most): OS
    • RAID10 with all 4 disks: Data - OR - 2 mirrors: data separated by some critera

I would add some small and cheap OS disks separate from the four main disks, as you can get 60 GB consumer-grade Intel SSD for $50 and most consumer-grade motherboards have at least 6 SATA ports this is the option I would go with and just keep with a good OS disaster recovery process (a good OS volume image would suffice).

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+1 for avoiding RAID-5. Go RAID-1, RAID-10 or RAID-6, along with the rest of the suggestions above (keeping OS and Data separate etc) –  fukawi2 Sep 9 '13 at 3:35

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