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Unpartitioned space on RAID5, performance?

Discussion in 'Storage Drives' started by Yamahahahahaha, 30 Sep 2009.

  1. Yamahahahahaha

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    Joined: 11 Oct 2008

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    Location: London

    I currently have a 3 drive RAID 5 on a PERC 4/SC controller.

    I will be expanding it to a 5 drive RAID 5.

    As a result, there will be unpartitioned space on the array. This free space will presumably spread across all 5 drives in the array?

    If I don't partition this space, will I still get the benefit of those extra spindles, in terms of IOPs and lower random access times?
    Since the drives are part of the array I expect there will be, but confirmation would be nice.

    There are risks involved with partitioning, which I do not need to face right now. Speed is more important than storage space.

    Thanks, Yama



    I figured this would be a better place to put this topic, rather than the Servers and Enterprise Solutions forum, don't prove me wrong ;)
     
  2. rpstewart

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    Joined: 11 Mar 2003

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    Location: Greenock, Scotland

    Extending the array will result in your current data being spread evenly across all five so you will get the benefit of higher transfer rates etc.
     
  3. Yamahahahahaha

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    Joined: 11 Oct 2008

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    Exactly what I wanted to hear :)

    Follow up question;

    Is it safer to resize a partition on an array, or just to create a whole new one?
    At the moment I have 'D' and 'E' on the array, shall I add an 'F' for the remaining space, or bloat up D and E equally?
     
  4. rpstewart

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    Joined: 11 Mar 2003

    Posts: 10,744

    Location: Greenock, Scotland

    Adding an 'F' is the safest option. Partitions need to be contiguous bits of disk so resizing both D & E will mean moving one of them (probably E) to make room to extend the other. Extending just E is reasonably safe though, it just depends how you want/need to use the space.
     
  5. Yamahahahahaha

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    Joined: 11 Oct 2008

    Posts: 3,836

    Location: London

    The space isn't very important at all, just need more IOPs and throughput for a minimal cost really.

    I've found a product by EASEUS which supports the PERC4/SC which would let me resize it, I think I'll buy that once the array has rebuilt.

    Thanks for your help!
     
  6. Zarf

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    Joined: 11 Jul 2007

    Posts: 2,527

    You don't even need to create a new partition to use the new space, If you're using Windows you can just run Diskpart and extend the partition to fill it up. Very quick and easy.
     
  7. PistolPete

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    DISKPART will only extend 'E' in his instance. 'D' will need to remain the same size.