Configure the storage area for shadow copies to go to a different NTFS volume on a Windows 2008 and 2012 servers

Problem

Backup jobs fail due to VSS related errors indicating either a lack of disk space or IO that is too high to maintain the shadow copies.

Solution

By default, Microsoft Volume Shadow Copy Services (VSS) is configured to write the shadow copies of a volume to a storage location on the volume itself.  This can result in very high IO 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 2008 and 2012 servers can be configured to use a different NTFS volume.  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=<drive being backed up> /on=<drive to store the shadow copy> /maxsize=<percentage of disk space to allow to be used>

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

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

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

The current shadow copy storage locations for each volume may also be confirmed by running the following command:

 

vssadmin list shadowstorage