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goofology
Asked: 2020-02-29 10:23:37 +0800 CST

Microsoft Storage Spaces Write-Back Cache exists on HDD-only single-tier parity disk?

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I created a parity storage space on 3x external USB 4tb HDD attached to a Windows 10 1809 machine. I then moved those HDDs to a Server 2019 1809 machine and added 1x additional 4tb HDD.

I noticed there is an existing 32mb write-back cache in this HDD-only single-tier parity storage space.

Is there a way to determine where this is located or why it exists? I'm unsure if it existed on W10 machine, never checked, but imagine it must've. Only noticed it on Server 2019 machine because Server Manager displays it in the Storage Pools information.

Does Storage Spaces attempt to use host device SSDs/RAM for WBC even if they are not part of the pool? Why? Both W10 and Server 2019 machines have SSD host OS drives.

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cache storage windows-server-2019 write-back

1 Answers

  1. As per Microsoft documentation for parity Pools default 32MB cache will be always created. https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn387076%28v%3dws.11%29 However, I've never found which media WBC is using, I assume it will use RAM for cache. Unfortunately, you can't change this value after the space was created.

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