NetBackup status code: 2821
Message: Hyper-V policy restore error
Explanation: On a Hyper-V restore operation, a connectivity issue between the Hyper-V host and the media server causes bptm to fail to write to the socket.
Recommended Action: Try the following:
Update the NIC drivers and firmware if necessary.
Ensure that the network hardware between the media server and the client operates properly.
Add NetBackup processes and directories to the Antivirus Exclusion List since antivirus applications may close the established socket.
Increase TCP resiliency on the Windows hosts (master servers, media servers, and clients) by setting the TcpMaxDataRetransmissions registry key to a value of 10. The default value is 5.
More information is available from Microsoft about the TcpMaxDataRetransmissions registry key:
Click here to view technical notes and other information on the Cohesity Technical Support website about this status code.