Minimizing the amount of unnecessary downloads from cloud storage provides multiple benefits:

  1. Reduced Internet bandwidth usage.
  2. Lower egress costs.
  3. Improved CacheDrive performance.

Here are some common causes of avoidable downloads.

Thumbnail Generation

Windows File Explorer (and other file managers) may generate thumbnails for easier file management.  To generate thumbnails for files that are not in cache, the files must be downloaded, which can result in large amounts of data being pulled from the cloud.  To disable thumbnail generation in Windows File Explorer, reference the screenshot below:

  1. Go to the View tab in File Explorer.
  2. Click Options.
  3. In the Folder Options dialog, go to the View tab.
  4. Disable the "Always show icons, never thumbnails" option.

You may also be able to avoid creating thumbnails by using view modes that do not use thumbnails (for example, the Details view).

Thumbnails can also be disabled with Group Policy:

  1. Run gpedit.msc.
  2. Navigate to User Configuration -> Administrative Templates -> Windows Components -> File Explorer.
  3. Disable the following options as needed:
    • Turn off the display of thumbnails and only display icons
    • Turn off the display of thumbnails and only display icons on network folders" options as needed

For more information, see the following article:

How to Disable Thumbnails in Windows 10

Indexing File Contents for Search

By default, Windows does not index the contents of files on network shares and drives.  If it is enabled or done by a third-party application, files that are out of cache must be downloaded before the contents can be indexed.  Indexing metadata for search does not require the file contents to be downloaded.

One simple way to check if Windows is indexing the network share is by going to Windows Settings, then Windows Search settings, and checking the Indexed Items count before and after creating a new file in the share.  If the number does not change, then the share is not being indexed for contents or metadata.

Security and AV Software

Security and anti-virus software may be scanning the contents of files in a share for malware.  If the file is out of cache, it must be downloaded before scanning.

Checksum-based Incremental Backups

Some Administrators like to keep a separate copy of their data onsite.  After the initial full backup, most will use incremental backups to keep their separate copy up to date with changes on the CacheDrive.

If these incremental backups detect file content changes by comparing checksums, out of cache files must be downloaded to calculate the checksums used.  Using metadata-based file change detection (modification date, archive bit, etc.) may help avoid these extra downloads.