By default, Microsoft Volume Shadow Copy Services (VSS) is configured to write the shadow copies of a volume to a folder on the volume itself during a backup job.  This can result in very high I/O or low disk space problems during the backup of a volume since the drive is experiencing load from the backup reading files, load and disk space usage from VSS reading from and writing to the shadow copy, and load and disk space usage from any other applications on the system using that same volume.  The shadow copy storage location of each volume on a Windows server can be configured to use a different NTFS volume.

Note: This functionality is only available on Server editions of Microsoft Windows and is not available on desktop versions of the operating system.  For desktop versions of Windows (Windows 7, 8, 8.1, 10), the shadow copies of a volume are written to the volume itself and this cannot be altered.

The ideal situation would be to have a separate drive dedicated to shadow copies that is not being backed up and is also not the drive containing the paging file.  If this is not possible, specifying a separate drive that contains the paging file is typically still better than storing the shadow copy on the drive being backed up.  In order to configure the shadow copy storage location for each volume, the following steps can be taken:

1.  Open a command line as Administrator by browsing to C:\Windows\System32.  Right-click on cmd.exe and pick Run as administrator

2.  Run the following command:

vssadmin add shadowstorage /for= /on= /maxsize=

For Example:
If the VSS shadow copies of the D: drive will be stored on the C: drive and allowed to use up to 90% of the free disk space on C:, the command would look like:

vssadmin add shadowstorage /for=d: /on=c: /maxsize=90%

If the command was performed successfully, the following message will be shown:
Successfully added the shadow copy storage association

More details in following MS article:

Vssadmin add shadowstorage

Vssadmin list shadowstorage

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The current shadow copy storage locations for each volume may also be confirmed by running the following command from the command line:
vssadmin list shadowstorage

Backup jobs fail due to Microsoft Volume Shadow Copy Service (VSS or snapshot) related errors indicating either a lack of disk space or I/O that is too high to maintain the shadow copies.