Creating VSS snapshot Error: Failed to create snapshot: Backup job failed. Cannot create a shadow copy of the volumes containing writer’s data. VSS asynchronous operation is not completed.(Insufficient Storage for VSS Error “0x8004231F or Error: VSSControl: -2147467259”)

问题与背景：

使用Veeam for agent备份的时候（https://www.veeam.com/free-backup），遇到以下错误消息：
“Creating VSS snapshot Error: Failed to create snapshot: Backup job failed. Cannot create a shadow copy of the volumes containing writer’s data. VSS asynchronous operation is not completed。

解决办法：

https://www.veeam.com/kb1794

这个问题是因为某些分区卷影存储空间太小。将其设置为每个分区的20％，重新启动即可正常工作！

vssadmin resize shadowstorage /for=C: /on=C: /maxsize=20%
vssadmin resize shadowstorage /for=D: /on=D: /maxsize=20%