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Storage Spaces simple parity - add another column set, double the parity as well? RRS feed

  • Question

  • Hello,

    I am running an eight drive simple parity (column size = 8) vdisk, and would like to double the size by adding another 8 hard drives to the same vdisk. 

    Will I have another parity disk as a result of this (meaning: one disk can fail from both "column sets") or will the new 16 drive partition still only tolerate a single disk fault? 

    Sunday, February 16, 2020 7:47 AM

Answers

  • Hi ,

    >>Storage Spaces simple parity

    Did you mean single parity? If yes, using single parity can only safely tolerate one hardware failure at a time: if you're rebooting one server when suddenly another drive or server fails, you will experience downtime.

    For more details about single parity, please refer to the following link:

    Single parity

    If you add 8 hard disk to the same vdisk, your virtual hard disk is still single parity. So the column will still equal to 8. This will not change.

    If you want to increase pool capacity, you need to expand pool capacity in sets of eight disks.

    For your reference:

    Best Regards,

    Candy


    Please remember to mark the replies as an answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com   

    • Marked as answer by Jultsu Tuesday, February 18, 2020 1:30 PM
    Tuesday, February 18, 2020 7:37 AM
  • You’ll get 8x increase, but the fault tolerance stays the same if you’re using a single parity.

    Blog: https://thesystemcenterblog.com LinkedIn:

    • Marked as answer by Jultsu Tuesday, February 18, 2020 1:30 PM
    Tuesday, February 18, 2020 7:45 AM

All replies

  • Hi ,

    As far as I know, if you configure simple parity, there will be no fault tolerance.

    Best Regards,

    Candy


    Please remember to mark the replies as an answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com   

    Monday, February 17, 2020 8:29 AM
  • Hello,

    By "no fault tolerance" I would understand that the array cannot survive even a single drive failure. Can you please explain why this would be the case?

    • Edited by Jultsu Monday, February 17, 2020 1:42 PM
    Monday, February 17, 2020 1:40 PM
  • Hi,

    Did you have a look over here?

    Storage Spaces Frequently Asked Questions (FAQ)
    https://social.technet.microsoft.com/wiki/contents/articles/11382.storage-spaces-frequently-asked-questions-faq.aspx

    Quoting from the above link:

    What properties can I change after creating a storage space?

    Upon creating a storage space, certain fundamental properties are locked in place. These fundamental properties include the provisioning type (thin or fixed), the resiliency type (simple, mirror, or parity), the number of columns the storage space striping requires, and the striping interleave.

    After creating a storage space, you can change properties that do not affect fundamental characteristics, such as the size of the storage space and its name.

    So if you want to use more columns, you would have to re-create the whole resiliency.

    Best regards,
    Leon


    Blog: https://thesystemcenterblog.com LinkedIn:

    Monday, February 17, 2020 2:14 PM
  • Hello, and thank you for the reply as well,

    However, this is also missing the point. The original question was not about increasing column count; it was about expanding the original array by adding the same amount of drives to it (and by this, maximising the performance) but would it also mean that one of the new eight disks being added would function as a parity drive as well (i.e. I would get 7*HDD in raw storage), or will I get an 8*HDD increase in raw storage instead?



    • Edited by Jultsu Monday, February 17, 2020 4:24 PM
    Monday, February 17, 2020 4:22 PM
  • Hi ,

    >>Storage Spaces simple parity

    Did you mean single parity? If yes, using single parity can only safely tolerate one hardware failure at a time: if you're rebooting one server when suddenly another drive or server fails, you will experience downtime.

    For more details about single parity, please refer to the following link:

    Single parity

    If you add 8 hard disk to the same vdisk, your virtual hard disk is still single parity. So the column will still equal to 8. This will not change.

    If you want to increase pool capacity, you need to expand pool capacity in sets of eight disks.

    For your reference:

    Best Regards,

    Candy


    Please remember to mark the replies as an answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com   

    • Marked as answer by Jultsu Tuesday, February 18, 2020 1:30 PM
    Tuesday, February 18, 2020 7:37 AM
  • You’ll get 8x increase, but the fault tolerance stays the same if you’re using a single parity.

    Blog: https://thesystemcenterblog.com LinkedIn:

    • Marked as answer by Jultsu Tuesday, February 18, 2020 1:30 PM
    Tuesday, February 18, 2020 7:45 AM