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Unable to retrieve next block transmission command when backing up to tape from a Linux repository


When backing up to tape from a Linux repository, the following error may appear:

Unable to retrieve next block transmission command. Number of already processed blocks: [number of blocks].

The log file contains the following information:

cli| WARN|[Tape] Default EOM Warning (2147483648)! Initial free space: 5251268608, Written (this tape): 3104833536, Total written: 3104833536
     ERR |Asynchronous data reader has failed.
     ERR |End of file
     >>  |--tr:Cannot read data from the socket. Requested data size: [952531].
     >>  |--tr:Failed to unserialize buffer with data.
     >>  |--tr:Failed to unserialize data block.
     >>  |--tr:Failed to unserialize FIB block.
     >>  |Unable to retrieve next block transmission command. Number of already processed blocks: [4944].
     >>  |--tr:Next asynchronous read request cannot be processed.


By default, most SSH servers have set a timeout to disconnect idle clients. After idling for some time, your connection is dropped.


To make the keep alive settings available for all connecting clients, it is recommended to configure the settings in server side.

Modify the /etc/ssh/sshd_config and add the following lines :

ClientAliveInterval 30
TCPKeepAlive yes
ClientAliveCountMax 99999

After setting this, you have to restart the SSH server by issuing this command :

sudo service ssh restart

Note that restarting SSH server will not disconnect existing connecting clients via SSH.

More information

Keep in mind that these changes will affect all SSH connections.
KB ID: 1872
Product: Veeam Backup & Replication
Version: 7.x
Published: 2014-04-21
Last Modified: 2020-08-13
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