Command Line (Client or Server OS)
All commands below should be run from an administrator command prompt.
Use vssadmin list shadowstorage to view existing shadow storage associations. If no shadow storage exists for any volume, the command response will be “No items found that satisfy the query.”
If no association is listed for the volume, run vssadmin add shadowstorage to change the location of the shadow storage area. For example, to redirect shadows from D: to E:
vssadmin add shadowstorage /for=D: /on=E: /maxsize=200GB
If a shadow storage association already exists, run vssadmin resize shadowstorage to change the size of the shadow storage area. For example, to redirect shadows from D: to E:
vssadmin resize shadowstorage /for=D: /on=E: /maxsize=200GB
The /maxsize parameter is not optional, but can be set as /maxsize=UNBOUNDED. Otherwise, a value of 15-20% of the source volume’s size is generally recommended for busy servers.
How to Check Which Volume is Causing the Error
In some cases, it may not be obvious which volume needs to be modified. To isolate the problem, perform the following steps within the VM guest OS that cannot be backed up or replicated.
Create and then delete a shadow copy of each volume, one at a time. To access the GUI, right click any volume and choose Configure Shadow Copies. On older operating systems, this may instead be a tab in Properties. In the Shadow Copies utility:
- Select a volume;
- Click Create Now;
- If this is successful, select the shadow copy and click Delete Now;
- Repeat steps 1-3 for each volume.
This can also be performed using the Diskshadow utility, which may provide a better match for the behavior of the VSS API used by Veeam Backup & Replication.
If the affected volume has sufficient free disk space, the shadow storage limit may be too small. Redirect the shadow copies as shown above, or increase the shadow storage limit.