The DPM service was unable to communicate with the protection agent RRS feed

  • Question

  • We currently have 2 hosts performing backups.  One of the hosts are off-site , and perform incremental backups.  A lot of the time, we are greeted with the following error.  These backups sometimes run for 4-10 hours, then fail.  Other times, these backups run just fine without a problem.  What could possibly be causing this from happening?  The backups on the main host that perform full-backups are running fine.  The incremental backups are causing these errors.

    Type: Synchronization
    Status: Failed
    Description: The DPM service was unable to communicate with the protection agent on (ID 52 Details: The semaphore timeout period has expired (0x80070079))
    More information
    End time: 5/31/2013 2:15:33 PM
    Start time: 5/31/2013 9:49:16 AM
    Time elapsed: 04:26:17
    Data transferred: 597.06 MB
    Cluster node -
    Source details: \Backup Using Child Partition Snapshot\Mars Virtual Machine(Mars Virtual
    Protection group: Disaster Recovery Group

    Friday, May 31, 2013 7:47 PM

All replies

  • Hi,

    Diagnostic steps when "Semaphore timeout" is hit during network transfer - it's basically a networking problem that needs to be diagnosed.

    1. Check if the protected server (sender) or DPM (receiver) was under stress or inaccessible during the time of failure – from event logs from both the machines. Retry should work if the packet loss was because of either of the servers being inaccessible or under stress for a period.

    2. Check if the network between the PS and the DPM is flaky – retransmit count from ‘netstat –s’ or perfmon counters can give an idea.

    3. If the network is expected to be flaky, setting a higher TCP/IP maximum retransmission timeout as described in might help -increase the TcpMaxDataRetransmissions to 10 or more.

    4. Else contact network support engineer to diagnose the packet loss issue – netmon captures from both machines, packet route and network layout/devices will be required to start the investigation.

    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Saturday, June 1, 2013 7:34 PM