A backup job for a Windows machine being processed using Veeam Agent for Microsoft Windows fails during the disk read operation with either of the following errors:
The system cannot find the file specified. Asynchronous read operation failed Failed to upload disk. Agent failed to process method {DataTransfer.SyncDisk}.
The device is not ready. Failed to schedule asynchronous read operation Failed to upload disk. Agent failed to process method {DataTransfer.SyncDisk}.
Example job report:
These errors occur either because:
Veeam Agent for Microsoft Windows issues requests to the Microsoft Software Shadow Copy Provider to create a volume shadow copy during a backup. If the shadow copy cannot be created or is unexpectedly removed during the backup operation, the backup job will fail.
The 'volsnap' error will provide details about which drive is impacted and the underlying issue.
For example:
The most common Volsnap error reported by customers is:
Event ID: 25 Description: The shadow copies of volume X: were deleted because the shadow copy storage could not grow in time. Consider reducing the IO load on the system or choose a shadow copy storage volume that is not being shadow copied.
As the error indicates, the shadow copy was deleted when the shadow copy could not grow. Since Veeam Agent for Microsoft Windows was reading from that shadow copy, the backup immediately fails with, "The system cannot find the file specified. Asynchronous read operation failed." The underlying cause, as explained in the error, is that the disk's IO load was too high. The solution is to reduce the disk IO load, implement faster storage, or redirect shadow copies to a volume with less IO load. Customers most commonly select redirection of shadow copies, as it requires no infrastructure changes.
The next most common Volsnap error reported by customers is:
Event ID: 36 Description: The shadow copies of volume X: were aborted because the shadow copy storage could not grow due to a user imposed limit.
Like Event ID:25 above, the shadow copy could not grow and instead was deleted. This again causes the Veeam Agent for Microsoft Windows backup job to fail with the error, "The system cannot find the file specified. Asynchronous read operation failed." In this case, the resolution is to review the shadow copy storage limitations or redirect shadow copies to a volume with more storage space.
Additional examples of Volsnap errors can be found in the More Information section of this article.
The most common solution for almost all issues is redirecting shadow copy storage to a volume with sufficient free space and plenty of available IOPS.
Click a section below to expand and view instructions.
Common Volsnap Errors Reported by Customers
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