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S2D - hot spares RRS feed

  • Question

  • Hi,

    I am planning a 2-node S2D cluster. I think I'm all set in terms of configuration but one thing I'm not sure about is hot spares.

    Obviously these are set at the pool level rather than the tier, so if I wanted hot-spares for both capacity and cache disks, does that just happen; if I assign 2 SSDs as spares, will they only be spares for the fast tier?

    I'm thinking 16 capacity disks + 2 spares and 4 cache disks + 2 spares per node. 24 total.

    Or am I going mad even thinking about this? Is it totally unneccessary for fast tiers?

    Thanks

    Thursday, March 8, 2018 3:45 PM

Answers

All replies

  • Actually, is the whole hot spare thing a waste of time in S2D?

    Reserve capacity

    For this to work, you need to set aside some extra capacity in the storage pool. You can think of this as giving the contents of a failed drive “somewhere to go” to be repaired. For example, to repair from one drive failure (without immediately replacing it), you should set aside at least one drive’s worth of reserve capacity. (If you are using 2 TB drives, that means leaving 2 TB of your pool unallocated.) This serves the same function as a hot spare, but unlike an actual hot spare, the reserve capacity is taken evenly from every drive in the pool.

    Thursday, March 8, 2018 4:20 PM
  • Hi,

    >> Actually, is the whole hot spare thing a waste of time in S2D?

    Based on my experience, hot spare disk is not required for a S2D cluster.

    And I haven’t seen any other people using hot spare for S2D cluster in any cases.

    Here are some documents for your reference:

    https://docs.microsoft.com/en-us/windows-server/storage/storage-spaces/storage-spaces-direct-overview

    Best Regards,

    Mary


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    • Marked as answer by Lanky Doodle Sunday, March 11, 2018 11:03 AM
    Friday, March 9, 2018 3:15 AM
  • Thanks Mary.

    One other question - I've read that capacity drives should be in multiple of cache drives, so 2 cache drives = 4 capacity drives, or 1:2 ratio.

    Does the ratio have to be 1:2? I was thinking 18x 1.2TB SAS with 6x 400GB SSD, so the ratio would be 1:3 cache:capacity, and it exceeds the recommended 10% cache space to capacity space.

    That way I have flexibility in pool creation - one big pool or 2 pools with 9x capacity and 3x cache or even 3 pools with 6x capacity and 2x cache. All would be 1:3 ratio exceeding the 10%.

    Sunday, March 11, 2018 11:14 AM
  • Hi,

    >> Does the ratio have to be 1:2?
    Not needed.

    Best Regards,

    Mary


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

    • Marked as answer by Lanky Doodle Monday, March 12, 2018 11:47 AM
    Monday, March 12, 2018 2:14 AM
  • Looks like you possibly can set hotspares

    Set-PhysicalDisk -FriendlyName "PhysicalDisk4" -Usage HotSpare

    Link below:

    https://docs.microsoft.com/en-us/powershell/module/storage/set-physicaldisk?view=win10-ps

    Sunday, June 30, 2019 1:25 AM