Storage Overheads RRS feed

  • Question

  • Hi,


    I understand that WHS uses mirroring to protect data from a disk failure. Does this require a 100% overhead on storage capacity (2Tb of data requires 4Tb of disks), or is there some compression involved?



    Friday, February 22, 2008 7:12 AM

All replies

  • Hello, you can select which shares to mirror, so only the stuff you actually worry about will be taking up extra space.  But yes, it is 1:1.  Compression probably wouldn't achieve very much as, for many home users anyway, their space-hungry files are likely to be media which is already compressed and hence can't be compressed further.


    Hope that helps.


    Friday, February 22, 2008 9:04 AM
  • WHS does not use Mirroring, nor do they call it that.

    Mirroring is a RAID technology where everything written on one disk is written to another.  That occurs at the disk level, i.e. same i/o commands and data sent to two different disks.  It is a "matched" pair of disks, i.e. the disk sizes at least have to be the same or part of one disk will be unused.  Mirroring is performed by RAID software, with a program to allow you to choose the disks, set up the array etc.

    WHS uses file duplication where the same FILES are sent to two different disks.  Which disks the files are sent to are determined by WHS (DE) on-the-fly and can be any two disks in your system, and in fact can and will change from hour to hour, day to day.

    Microsoft touts their file share as "superior to RAID".  OTOH it doesn't work too well ATM, causing corruption issues that are legend already.
    Friday, February 22, 2008 1:17 PM