Snapraid useable storage Question

  • Hello,


    I think it is a simple question but for me i am not sure so i better ask.


    If i have 4x4TB HDDs and i want to use them with mergerfs and snapraid then how much will be my final useable storage?


    One HDD will obviousily be the parity drive and 4TB HDD has roughly about 3,64TB of useable storage. Times 3 of the left over HDDs wpuld be 10,91TB of useable storage excluding the parity drive right?

    The reason is that i have a "experimental" NAS where i just run tests etc. and i want to turn it in a better properly useable NAS before i build my big NAS project. But i need to know if all my data will fit on it so that is why i need to know how much useable storage i will end up with.

  • Copaxy

    Added the Label OMV 5.x
  • The parity unit is not usable storage. The data units add up to their individual capacity.


    One HDD will obviousily be the parity drive and 4TB HDD has roughly about 3,64TB of useable storage. Times 3 of the left over HDDs wpuld be 10,91TB of useable storage excluding the parity drive right?

    Yes. 1 unit of parity (4TB) plus 3 units of data (4 + 4 + 4TB) = 12TB of data. Approximately 10.9 TB usable.


    It is advisable to always have at least 15% or 20% free space on the disks for best performance.

    The best thanks to the help provided is to report what your solution was. The next one will thank you :thumbup:

  • The parity unit is not usable storage. The data units add up to their individual capacity.

    Ah good.. then my thought was not wrong.

    Thank you :)

    It is advisable to always have at least 15% or 20% free space on the disks for best performance.

    Okey, yeah for my new project NAS i will definitely have this. But for this one it is kind of close to full storage...

    I think my data is approximately 10TB. So i theoretically would have 900GB left.

    But as i say this is just my experimental one so i just keep it as a additional storage until my new project NAS will be build. So i guess it is fine for a transition storage space.

  • Copaxy

    Added the Label resolved
  • It is advisable to always have at least 15% or 20% free space on the disks for best performance.

    What is the basis for this suggestion? What type of performance are you referring to?

    --
    Google is your friend and Bob's your uncle!


    OMV AMD64 6.x on headless Chenbro NR12000 1U 1x 8m Quad Core E3-1220 3.1GHz 16GB ECC RAM.

  • What is the basis for this suggestion? What type of performance are you referring to?

    In general, I have always read that using a disk to the limit of its capacity leads to the fragmentation of files on any system, some more than others. It will also depend on how the disk is used. Copying files once and not moving them is not the same as writing and deleting continuously. It is true that linux and EXT4 is very efficient in this regard. But it is not free from this drawback either. Maybe 15% free space is over the top. Correct me if so, please. Always willing to learn. :thumbup:

    The best thanks to the help provided is to report what your solution was. The next one will thank you :thumbup:

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