WSUS: revert "Download Express Installation Files" setting

Chad _ 21 Reputation points
2021-02-04T23:04:32.633+00:00

Good afternoon,

I inherited a WSUS server (2012 R2, version 6.3.9600.18694) with about 200 servers (2012 R2-2016 with 2019 to be added soon) getting updates from it. Like many others, I noticed disk consumption on the WSUS server really spiking. Sure enough, it appears to be because the "Download Express Installation Files" setting is turned on. I'm familiar with the feature and what it's for, but can I simply uncheck it or are there some gotchas related to doing so? The vast majority of our servers are on 1 GB LAN. Any feedback is appreciated.

Thanks,

Chad

Windows for business | Windows Server | User experience | Other
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3 answers

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  1. Adam J. Marshall 10,356 Reputation points MVP
    2021-02-05T00:37:23.893+00:00

    Nope, Go ahead an uncheck it - wait 24 hours, then run the server cleanup wizard and that should get rid of the bulk of the extra data.

    1 person found this answer helpful.

  2. Rita Hu -MSFT 9,661 Reputation points
    2021-02-05T07:30:46.033+00:00

    Agree with Adam.

    Uncheck the Download Express Installation Files option and run the Server Cleanup Wizard. We would not sync useless updates the next time.

    Thanks for your time.

    Regards,
    Rita


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  3. Rita Hu -MSFT 9,661 Reputation points
    2021-02-08T08:33:11.403+00:00

    Hi Chad-1508,

    My description of the above may not be accurate. The following is a detailed description of the supplement.

    The express installation files feature is an update distribution mechanism. We could use express installation files to limit the bandwidth consumed on our local network, but at the cost of bandwidth consumption on your Internet connection. By default, WSUS does not use express installation files. To better understand the tradeoff, we first have to understand how WSUS updates client computers.

    Updates typically consist of new versions of files that already exist on the computer being updated. On a binary level these existing files might not differ very much from updated versions. The express installation files feature is a way of identifying the exact bytes that change between different versions of files, creating and distributing updates that include just these differences, and then merging the original file with the update on the client computer. Sometimes this is called delta delivery because it downloads only the difference, or delta, between two versions of a file.

    When you distribute updates by using this method, it requires an initial investment in bandwidth. Express installation files are larger than the updates they are meant to distribute. This is because the express installation file must contain all the possible variations of each file it is meant to update.

    The upper part of the "Express Installation Files Feature" illustration depicts an update being distributed by using the express installation files feature; the lower part of the illustration depicts the same update being distributed without using the express installation files feature. Notice that with express installation files enabled, you incur an initial download three times the size of the update. However, this cost is mitigated by the reduced amount of bandwidth required to update client computers on the corporate network. With express installation files disabled, your initial download of updates is smaller, but whatever you download must then be distributed to each of the clients on your corporate network.
    65240-22.png

    The file sizes in the "Express Installation Files Feature" illustration are for illustrative purposes only. Each update and express installation file varies in size, depending on what files need to be updated. Further, the size of each file actually distributed to clients by using express installation files varies depending upon the state of the computer being updated.

    Regards,
    Rita


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