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Windows Storage Spaces with Parity using loads of space up

Discussion in 'Software' started by neocleous, 22 Feb 2016.

  1. neocleous

    neocleous Member

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    Hi all,

    I have set up a Storage Spaces with parity on 10 2TB hard disks.

    I am using just over 10TB but storage spaces is reporting that 16TB is in use. I assume that is for parity data but that is just excessive.

    Is there a way to reduce the aggressive redundancy back I only really want RAID 5 so one drive redundancy.
     
  2. saspro

    saspro IT monkey

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    There's no real way that I know of removing it without backing the whole lot up then rebuilding the pool.

    Storage Spaces used 256mb block slabs so can be very inefficient (compared with true RAID) if you've got lots of files less than the slab size
     
  3. Buzzons

    Buzzons Active Member

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    Default is 256KB isn't it? but you can change it when creating the pool.

    There's no way to change it as far as I'm aware after pool has been created though.
     
  4. neocleous

    neocleous Member

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    I am using it to store films and TV so they are large files. Storage Spaces is absolutely shocking I have nothing positive what so ever to say about it.

    It doesn't give you any detailed options like data slab size it is very basic probably to not scare users away but it needs a lot of work and a lot more options.

    I am now trying to get my data off it which is infuriating me to say the least!!!
     
  5. phuzz

    phuzz This is a title

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    Firstly it's worth noting that slabs are not the same as stripes, they're just the basic unit that Storage Spaces (SS to save me typing) uses. When you add the first file it will create a number of slabs based on the type of space you're using, but you can keep adding files until you fill one of those slabs, then it creates more.
    There's not a lot of documentation on it, but it looks like SS reports the amount of space used up by the 256MB slabs, rather than the actual data. So, if you kept adding (eg) 100MB files, you'd see the used space jump every three files as you fill up a 'slab's worth' of space, rather than going up by each file.
    The other part of is that, (if I'm interpreting the documentation correctly), SS will create at least one slab per drive each time for a parity space. So, if you've just added a file which was just too big to fit in the existing slabs, in your case it would create ten slabs, totalling 2.5GB(!)
    Add that to the roughly 33% overhead from the parity data and it might explain what you're seeing, but SS doesn't seem to be that space efficient.
    I might well be wrong about some of the above, the MS blogs and documentation are clear about some parts, but gloss over others.
     
  6. neocleous

    neocleous Member

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    Wel my SS is completly broken at the moment. The data is all there but I can't copy anything from it. It is bursting to 140MB/s for a few GB's then crashing to zero and going up to a few hundred KB's.

    It is totally unusable and it is stuck on "Stopping Optimisation" and I can't get it out of it.

    How can I fix this so I can get everything off it and never ever use it again!!!!
     
  7. saspro

    saspro IT monkey

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    What OS version are you using SS on?
    What's the underlying hardware?
     
  8. neocleous

    neocleous Member

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    Windows 10

    Intel Core i5 2500K, 8GB RAM, Asus P8Z68 V-Pro and a 4 port SATA add in card.
     
  9. davidbrown1988

    davidbrown1988 Member

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    This may or may not help you but there are a couple of powershell commands I have that have helped me in the past with Storage spaces:

    The below command will report back storage space efficiency. Obviously replace the drive letter with yours:
    Optimize-Volume -DriveLetter E -Analyze -Verbose

    #This command will consolidate slabs, only worth running if efficiency is less than 95% or so. Again replace drive letter with yours:
    Optimize-Volume -DriveLetter E -SlabConsolidate -Verbose


    To be fair though I'd never recommend anyone touches storage spaces in parity mode unless you are using powershell and ssd's to custom set write buffer. the performance is beyond terrible without this.


    Also as a general warning if you set a storage space to thin provisioning and set the max drive space to say 10x your current storage and then encrypt it with bit locker it will need 10x your drive space to recover a broken partition and decrypt. I lost about 6tb of data because of this a far while back. As stupid as that is. So even if the drive is 1tb it'd need 10 tb to decrypt and recover.
     
    Last edited: 26 Feb 2016
  10. davidbrown1988

    davidbrown1988 Member

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    And for reference if anyone is wondering i store the below data in a 3 way parity storage space:
    3.53 tb of data
    and it uses - 5.63tb of space across the pool.
     
  11. neocleous

    neocleous Member

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    Well I'm not sure how but the drives are out of 'Stopping Optimisation' and are behaving normally so I am backing everything up and putting Storage Spaces behind me! They are not fit for purpose and need a lot more options.

    I'm going to use Freenas on another PC and share across the network.
     

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