Windows Backup // Veeam Agent Backup fails - Error ID 8193

Question

Hi all,

we´ve got 4 fileserver and all have the same problem. The backup fails after some days. If you reboot the machine the backup runs fine almost always but after a few days it will fail again.
Veeam support suggested we should try to use the windows backup and it´s exactly the same with the same errror message.:

Volume Shadow Copy Service error: Unexpected error calling routine IVssAsync::QueryStatus. hr = 0x800706ba, The RPC server is unavailable.
.

Operation:
BackupComplete Event
Executing Asynchronous Operation

Context:
Current State: BackupComplete

-------------------

-vssadmin list writers:

Writer name: 'System Writer'
Writer Id: {e8132975-6f93-4464-a53e-1050253ae220}
Writer Instance Id: {9d9bbe46-51da-4d3e-8912-49061b1e233f}
State: [5] Waiting for completion
Last error: No error

Writer name: 'ASR Writer'
Writer Id: {be000cbe-11fe-4426-9c58-531aa6355fc4}
Writer Instance Id: {4cb5e147-fe9b-454d-90c7-07cb994ee33b}
State: [1] Stable
Last error: No error

Writer name: 'Shadow Copy Optimization Writer'
Writer Id: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f}
Writer Instance Id: {8568cf21-7053-4333-96a2-2a7021f826c8}
State: [1] Stable
Last error: No error

Writer name: 'Registry Writer'
Writer Id: {afbab4a2-367d-4d15-a586-71dbb18f8485}
Writer Instance Id: {b3695231-71f1-49d2-909f-f7d694b3d2b1}
State: [1] Stable
Last error: No error

Writer name: 'COM+ REGDB Writer'
Writer Id: {542da469-d3e1-473c-9f4f-7847f01fc64f}
Writer Instance Id: {539c9afc-7750-44fe-8470-9c9b2fe0e97f}
State: [1] Stable
Last error: No error

Writer name: 'WMI Writer'
Writer Id: {a6ad56c2-b509-4e6c-bb19-49d8f43532f0}
Writer Instance Id: {bb9ba80c-bec0-4013-90c9-a40fb610fa74}
State: [5] Waiting for completion
Last error: No error

Writer name: 'MSMQ Writer (MSMQ)'
Writer Id: {7e47b561-971a-46e6-96b9-696eeaa53b2a}
Writer Instance Id: {441ebcab-81fe-4158-9bae-4123e91474d4}
State: [5] Waiting for completion
Last error: No error

Writer name: 'SqlServerWriter'
Writer Id: {a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}
Writer Instance Id: {d15bd389-4d96-4484-924f-c3808d4640d0}
State: [1] Stable
Last error: No error

I´m running out of ideas.
Thanks in advance.

Jan

Answer 1

Hi Lintzen,

The following types of errors can cause RPC server unavailable:

1. The RPC service is stopped/failed on the remote computer.
2. The RPC Endpoint Mapper port TCP/135 is not accessible on the remote computer.
3. The Dynamic RPC range is blocked by firewalls installed between your computer and the remote computer.
   First, make sure the RPC endpoint mapper port 135 is listening on the remote computer. Use the following commands:
   netstat -ano | find "135"
   Make sure that the Remote Procedure Call (RPC) and DCOM Server Process Launcher services are in the running state and configured to start automatically.
   Access to the remote computer over RPC ports may be blocked by firewalls (this is a very common reason). The easiest way is to test for open/closed port is to use the following PowerShell command:
   Test-NetConnection 192.x.x.x -port 135
   Check whether "TcpTestSucceeded" is "True" in the running result. If port 135 (RPC Endpoint Mapper) is available, but the error “The RPC server is unavailable” is still present, you need to ensure that firewalls are not blocking communication on a dynamic RPC port range. The RPC Dynamic Ports is a TCP port range from 49152 to 65535, that must be open for RPC technology to work properly.
   The following two links also discuss issues similar to "8193":
   vss-error-8193
   the-rpc-server-is-unavailable-0x800706ba-win32-172.html

Hope my answer can help you!

Best Regards,
Xu Gu

Answer 2

Hi Xu Gu,

1. The RPC service is stopped/failed on the remote computer.
   2.The RPC Endpoint Mapper port TCP/135 is not accessible on the remote computer.
2. The Dynamic RPC range is blocked by firewalls installed between your computer and the remote computer.

Sadly non of these points is the issue. The backup is running for several days and then stops to work without any changes in the configuration.
What´s fixing it most of the time is a reboot of the source machine. The target side is never an issue.

Best regards,
Jan