FileSrv: Error: Sending data failed

I use Server UrBackup 2.5.31 (Linux 64bit) and latest precompiled Client 2.5.25 (RaspianOS, aarch64).

When I start the backup the index is created and when the transfer should start, client says

2024-06-19 17:17:57: Started connection to SERVICE_FILESRV
2024-06-19 17:17:57: FileSRV received 72
2024-06-19 17:17:57: FileSrv: Received data…
2024-06-19 17:17:57: FileSrv: Received a Packet.
2024-06-19 17:17:57: FileSrv: Sending file (normal) urbackup/filelist.ub metadata_id=0
2024-06-19 17:17:57: FileSrv: Mapped name: /usr/local/var/urbackup/data/filelist.ub
2024-06-19 17:17:57: FileSrv: Error: Sending data failed
2024-06-19 17:17:57: SERVICE_FILESRV finished
2024-06-19 17:17:57: Started connection to SERVICE_FILESRV

forever. No data is transmittet, server fails with “Error getting filelist of wgep001. Errorcode: TIMEOUT (2)”

BTW: I tried to compile the client myself, but that client can not connect to Server:
No result when looking up hostname “wss://MYHOSTNAME/socket”. Err: 22.

The server works OK, other clients work.

I have no more ideas to dive into the problem, has anyone an idea?


Could you try to narrow it down by disabling features? E.g. compression, encryption (since you use websockets you don’t need that anyways) – maybe try without websocket?

Thanks you for your answer. It is a little bit strange:

  • Backup “medium” subdirectory (5 GB) → fails
  • Backup only a very small subdirectory (few k) → works
  • Feature-changes: The problem seems to be the compression. If I disable the compression, the whole full backup (12GB) works fine.

But I do not understand why the small subdirectory works with compression. Is there a threshold "no compression if size is smaller than x k?