Raid Setup (new harddrive)

Discussion in 'General Hardware' started by Bman, Jul 25, 2008.

  1. Bman

    Bman OSNN Veteran Original

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    Alright, I am sure it's been asked. I am sure I can find tons of info on Google, but I'd rather ask here.

    I have 1 500GB SATA drive as my main drive.

    I have 1 500GB SATA drive as my storage/backup drive.


    Now I should be getting a new hard drive (500GB or 750GB)


    Can I, and how can I add that new harddrive to that backup drive, without losing everything or moving it? And what would be the best type of raid to use as a storage/backup drive? If I wanted to add even more drives later as well.

    Any tips and suggestions would be awesome.
     
  2. Dark Atheist

    Dark Atheist Moderator Political User Folding Team

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    in order to use raid the drives have to be the same size, and if possible same model, as to adding it to raid depends on what type of raid, if raid0 - i don't think you can keep all the info - if raid one i think you can
     
  3. Bman

    Bman OSNN Veteran Original

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    Well that is what I am asking, I guess in detail.

    I want to keep the data as is, the drive is 500GB.

    So I need to same harddrive (model as well) how do I add to it, I know I have to turn raid on in the bios, but every time I have done that in the past everything gets erased on the drive. And with Raid1 if that is my option, does that make it larger in size, or is it just mirroring it, or what?
     
  4. fitz

    fitz Just Floating Along Staff Member Political User Folding Team

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    *sigh* I tried to stay from this conversation.. I really did..

    The drives really don't have to be the same size. Most array controllers can handle a drive if it's a bigger capacity, the extra space will just go wasted and can't be used.

    RAID1 is just a mirror to provide redundancy - it won't add capacity.. it is also (normally) limited to 2 drives in the array.

    RAID0 can stripe the drives to add capacity and a slight performance boost but provides no data redundancy.. it also has the problem that if 1 drive fails in a RAID0 array, you lose the data on both drives, or if you have a 3 drive RAID0 array and one drive fails, you lose the data on all 3 drives. Basically, the more disks you add to a RAID0 array, the percentage chance of total data loss increases.

    RAID5, if your controller supports it, can do more than 2 drives in an array (in fact, you need a minimum of 3 drives to set up initially) and proves n-1 expansion where n is the number of drives in the array.. example: you have 3 drives that are 500GB each.. your total space in the array is the same as if you had 3-1 (n-1 or 2) drives.. or 1TB for 3x500GB drives in a RAID5 array. RAID 5 provides for expansion and redundancy for single drive failure and is fast for reading data but a bit slower on writing data.

    RAID10 or RAID01 requires a minimum of 4 drives and are slightly different in how they setup the array. They both do a combination of mirroring and striping of data but RAID10 is FAR superior in many ways than RAID01. I've written a long post about the differences before if you want to search the forums for it (too lazy to find it right now and don't want to type it all out again).

    edit: as far as keeping existing data on the drive, a RAID0/Stripe set will require both drives to be clean - meaning data will be lost. A RAID1/mirror should be non-destructive on creation.. it shouldn't have to delete the data, but I've seen some silly implementations of RAID with onboard controllers in particular that for some reason, wipe both drives no matter which RAID type you select. Really though I understand why they do that. SATA drives tend to have a higher incidence of drive errors and failures and it's nice to start a RAID array with a clean slate.

    You have a couple options depending on how your board is setup. If you have multiple SATA controllers, you can move your drive with the data to the independent/non-RAID controller ports and buy two new drives and connect them to the RAID controller ports and set them up in the array of your choosing (generally, I always recommend against RAID0 but people always seem to do it anyway).

    You can find out if the RAID1 creation will be a destructive process or not and try to setup a RAID1 array if it isn't destructive - but one of your goals was later expansion by adding more drives so a RAID1 probably won't work for you.

    If you take my advice and stay away from RAID0, you're left with either RAID5 or RAID10/01 and you would need to find out if your RAID controller supports these but they do require a minimum of 3 (for RAID5) or 4 (for RAID10/01) drives to start.
     
    Last edited: Jul 25, 2008
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  5. Bman

    Bman OSNN Veteran Original

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    Wow, that's a great deal of useful information.

    How would I find out if my controller supports it. I have a EVGA 780i SLI motherboard if that helps.
     
  6. Dark Atheist

    Dark Atheist Moderator Political User Folding Team

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    Storage I/O
    1 x UltraDMA133
    6 x Serial ATA 300MB/sec with support for RAID 0, RAID1, RAID 0+1, RAID5, JBOD
    1 x Floppy disk drive connector
     
  7. Bman

    Bman OSNN Veteran Original

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    So the best one RAID10 I don't support, but RAID01 is just as good?
     
  8. Dark Atheist

    Dark Atheist Moderator Political User Folding Team

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    fitz likes this.
  9. fitz

    fitz Just Floating Along Staff Member Political User Folding Team

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    If you know the model of your board, why don't you try looking up the specs on it to find out what your board will support?

    It's called searching for my post I mentioned to learn the differences..

    Thanks Carpo.. reps for not being lazy like me! :)
    again.. thanks :)
    can also look at this post in the same thread..
     
    Last edited: Jul 25, 2008
  10. Bman

    Bman OSNN Veteran Original

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    So RAID 0+1 is what I want, correct me if I am wrong.

    Now how would I go about doing that. I need 4 drives for that right? So if I were to do that with 4 500GB drives, how man space would I actually have?
     
  11. fitz

    fitz Just Floating Along Staff Member Political User Folding Team

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    only you can determine what you want.. I just provide information :)

    Need at least 4 drives.. when/if you want to expand the array, you'll need to do it in multiples of 2 drives.

    4x500GB drives would provide 1TB of raw space.

    edit: oh, and you won't be able to preserve data on an existing drive if you want to use it in the array.
     
  12. JPRuss

    JPRuss OSNN Addict Folding Team

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  13. Bman

    Bman OSNN Veteran Original

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    I would love to get a drobo, wanted one for awhile, but yes they are to expensive.