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Optimal use of Storage Space disks RRS feed

  • Question

  • It seems to me that Storage Spaces hardly uses the disks optimally, even if the Optimization tool would report 99% space efficiency.
    I have 2x 3TB drives, 3x 1TB drives and 2x 750GB drives. I was getting "Low Capacity" warnings, even though one of the 3TB drives showed only 2% utilization (since I had just added it). 

    Since I'm using Parity model, and I have Thinly provisioned space, it is quite difficult for me to gauge the actual utilization of the Storage Space. Even with minimal utilization of one of the largest disks, it still wants more. And as you all know, if I run out of capacity, I'm locked out of my data until I add another drive. I wouldn't want to risk that, so I decided to experiment. I removed both of the 750GB drives from the pool, and as the utilization of the new 3TB disk grew, the pool still only wanted one more drive. Well, problem solved, since now I had two 750GB drives that weren't in the pool, so I could just add them back and the pool would be happy again. 

    I guess next time I'm asked to add another disk, I'll just remove a disk and let it reshuffle the bits a bit and then re-add it.

    So my questions are:

    1) How can I gauge the true available space in a storage space?

    and more importantly

    2) Why doesn't Disk Optimization automatically reshuffle the columns or whatever in a manner that is most optimal to the system?
    Saturday, October 5, 2013 2:43 PM

All replies

  • Hi,

    For the issue, Storage Spaces provides advance notification of thinly provisioned storage spaces when the storage pool does not have enough capacity spread among a sufficient number of disks to continue to write new data. The default warning point is 70% capacity utilization.

    Regarding how to gauge the true available space in a storage space, I suggest you refer to the following example.

    A two column, two-way mirror space that uses thin provisioning in a four disk pool

    Two of the disks have 1TB capacity and two have 2TB capacity. Because a two column, two-way mirror space needs four disks (number_of_disks = NumberOfColumns * NumberOfDataCopies), it will evenly consume all four disks as it writes new data. When capacity utilization of the two 1TB disks reaches 70%, Storage Spaces will warn of a low capacity condition. Even though the entire pool has 3.2TB free capacity, the thinly provisioned space will soon not be able to write any more data because the 1TB disks are nearly fully consumed.

    You can easily keep individual storage spaces’ low capacity warning synchronized with each other and with the pool by following the guidance in the next section, “How do I increase pool capacity?” from the moment of creating the pool and through all subsequent expansions of the pool.

    I would like to share the article below with you:

    Storage Spaces Frequently Asked Questions (FAQ)

    http://social.technet.microsoft.com/wiki/contents/articles/11382.storage-spaces-frequently-asked-questions-faq.aspx#Why_do_I_have_a_low_capacity_warning_even_though_I_still_have_unused_pool_capacity

    Meanwhile, Thinly provisioned drive just can optimize Trim and Slab consolidation.

    For detail information, please refer to:

    Optimize your hard drive

    http://windows.microsoft.com/en-IN/windows-8/optimize-hard-drive

    Regards,


    Kelvin_Hsu

    TechNet Community Support

    Wednesday, October 9, 2013 2:27 PM
  • Hi, 

    And thanks for the reply.

    But my issue was the Optimize tool not having the same effect on the pool as removing and reattaching drives. 

    Friday, October 11, 2013 11:21 AM
  • Hi,

    Based on my knowledge, the Optimize tool doesn’t support Storage Spaces.

    So, in the Storage Space, we cannot use Optimize tool.

    Thanks for your understanding.

    Regards,


    Kelvin_Hsu

    TechNet Community Support

    Wednesday, October 16, 2013 2:51 AM
  • Hi

    I think this is incorrect, I am able to improve space efficiency with the Optimize tool by consolidating slabs. (Since I'm using parity model, it's not as simple as mirroring the drives.) So far as I know though, 3rd party defrag programs cannot optimize storage spaces. 

    Wednesday, October 16, 2013 9:42 AM
  • Hi

    As kelvin mentioned earlier about optimize Trim and Slab consolidation,I think it can explain this issue.

    Optimize your hard drive

    http://windows.microsoft.com/en-IN/windows-8/optimize-hard-drive

    If the drive type is Thinly provisioned ,it just can optimize Trim and Slab consolidation.

    Sunday, November 3, 2013 12:34 PM
  • Yes, slab consolidation is possible on my thinly provisioned storage space. However, as I have been trying to explain to you, it is not able to resolve the low capacity warnings, whereas removing and readding drives is able to resolve the situation, which comes simply from poor disk utilization.

    I guess I will not reach any MS engineers responsible for storage spaces logic via this forum, I'll just give up...

    Sunday, November 3, 2013 5:03 PM