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ReFS or NTFS and what Unit size? RRS feed

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    Hi,

    We are building a new Hyper-v cluster with a fibre connected SAN, what is the best practice regarding CSV storage?

    We now have a cluster with NTFS formatted CSV's with 64k unit size, (windows server 2012r2) the new cluster is based on Server 2016, when i search this item, some are telling me use 4K ReFS (default size) with Hyper-v, others are saying use 64K ReFs, others are saying use NTFS etc..

    FYI, we don't use compression or deduplcation, the main workload is VHDX files with server load, some virtual SQL servers.

    Could please someone shed some light on this?

    thanks!

    Wednesday, November 29, 2017 9:48 AM

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    Hi Bart.Michel,

    ReFS offers both 4K and 64K clusters. 4K is the default cluster size for ReFS, and we recommend using 4K cluster sizes for most ReFS deployments because it helps reduce costly IO amplification;

    Additionally, 4K cluster sizes offer greater compatibility with Hyper-V IO granularity, so we strongly recommend using 4K cluster sizes with Hyper-V on ReFS.  64K clusters are applicable when working with large, sequential IO, but otherwise, 4K should be the default cluster size.

    NTFS offers cluster sizes from 512 to 64K, but in general, we recommend a 4K cluster size on NTFS, as 4K clusters help minimize wasted space when storing small files. We also strongly discourage the usage of cluster sizes smaller than 4K. There are two cases, however, where 64K clusters could be appropriatePlease check the following article to learn the detailed information:

    https://blogs.technet.microsoft.com/filecab/2017/01/13/cluster-size-recommendations-for-refs-and-ntfs/

    Besides, here is an article about CSV cache to improve the performance, for your reference:

    https://blogs.msdn.microsoft.com/clustering/2013/07/19/how-to-enable-csv-cache/

    Best Regards,

    Anne

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

    • Proposed as answer by Tim CerlingMVP Thursday, November 30, 2017 2:48 PM
    • Marked as answer by Bart.Michel Monday, December 4, 2017 9:30 AM
    Thursday, November 30, 2017 10:07 AM

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    Hi Bart.Michel,

    ReFS offers both 4K and 64K clusters. 4K is the default cluster size for ReFS, and we recommend using 4K cluster sizes for most ReFS deployments because it helps reduce costly IO amplification;

    Additionally, 4K cluster sizes offer greater compatibility with Hyper-V IO granularity, so we strongly recommend using 4K cluster sizes with Hyper-V on ReFS.  64K clusters are applicable when working with large, sequential IO, but otherwise, 4K should be the default cluster size.

    NTFS offers cluster sizes from 512 to 64K, but in general, we recommend a 4K cluster size on NTFS, as 4K clusters help minimize wasted space when storing small files. We also strongly discourage the usage of cluster sizes smaller than 4K. There are two cases, however, where 64K clusters could be appropriatePlease check the following article to learn the detailed information:

    https://blogs.technet.microsoft.com/filecab/2017/01/13/cluster-size-recommendations-for-refs-and-ntfs/

    Besides, here is an article about CSV cache to improve the performance, for your reference:

    https://blogs.msdn.microsoft.com/clustering/2013/07/19/how-to-enable-csv-cache/

    Best Regards,

    Anne

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

    • Proposed as answer by Tim CerlingMVP Thursday, November 30, 2017 2:48 PM
    • Marked as answer by Bart.Michel Monday, December 4, 2017 9:30 AM
    Thursday, November 30, 2017 10:07 AM
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    Hi Bart.Michel,

    Just to check if the above reply could be of help, if yes, please mark useful reply as answer, if you have other concerns, welcome to feedback.

    Best Regards,

    Anne

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

    Monday, December 4, 2017 2:45 AM