[Help] TOS 7 bug: GUI rsync task causes TOSDaemon to consume 200% CPU
Posted: 28 Jul 2026, 01:16
Hello TerraMaster Technical Support,
I am reporting what appears to be a reproducible TOS 7 bug involving a GUI-created rsync backup task.
System details:
* Model: TerraMaster F4-425
* CPU: Intel Celeron N5095
* Memory: 16 GB
* TOS version: [insert exact TOS version]
* Source directory: /Volume1/files/
* Destination: Remote rsync module on another NAS
* Job created and started through the TOS rsync backup GUI
Problem:
When the rsync task is not running, TOSDaemon uses approximately 1–3% CPU and the CPU package temperature is approximately 52–60°C.
Immediately after starting the rsync task through the TOS GUI, TOSDaemon rises to approximately 194–200% CPU and the CPU temperature rises to approximately 71–78°C.
The rsync process itself uses very little CPU when launched by TOS. I measured the following during the GUI-managed task:
TOSDaemon CPU: 200.5%
rsync CPU: 0.7%
The GUI-generated command includes:
--progress
Example process:
/usr/bin/rsync -rlt --progress --no-o --no-g --no-perms --delete --exclude '#recycle/' --log-file=/Volume1/@rsync/Files_Backup.log --port=873 /Volume1/files/ [email protected]::files/
To isolate the issue, I stopped the GUI task and started the equivalent rsync command manually without the --progress option.
During the manually launched task, I measured:
TOSDaemon CPU: 3.2%
rsync CPU: 39.3%
This indicates that the high CPU usage is not caused by rsync itself or by the file transfer workload. It appears that TOSDaemon is consuming approximately two CPU cores while monitoring or parsing the output from the GUI-managed rsync process, possibly because of the --progress option.
Restarting TOSDaemon temporarily returns CPU usage to normal, but starting the GUI rsync task reproduces the issue immediately.
Steps to reproduce:
1. Create an rsync backup task through the TOS GUI.
2. Start the task.
3. Observe TOSDaemon CPU usage.
4. Stop the GUI task or restart TOSDaemon.
5. Run the equivalent rsync command manually without --progress.
6. Compare TOSDaemon and rsync CPU usage.
Expected behavior:
TOSDaemon should supervise the rsync task without consuming approximately two full CPU cores.
Actual behavior:
TOSDaemon consumes approximately 195–200% CPU for the duration of the GUI-managed rsync task, while the rsync process itself uses less than 1% CPU.
Possible cause:
TOSDaemon may be continuously reading or parsing rsync’s --progress output. Removing --progress from GUI-generated rsync commands, or reducing how frequently progress output is parsed, may resolve the issue.
Please let me know whether any additional diagnostics are needed.
Thank you,
I am reporting what appears to be a reproducible TOS 7 bug involving a GUI-created rsync backup task.
System details:
* Model: TerraMaster F4-425
* CPU: Intel Celeron N5095
* Memory: 16 GB
* TOS version: [insert exact TOS version]
* Source directory: /Volume1/files/
* Destination: Remote rsync module on another NAS
* Job created and started through the TOS rsync backup GUI
Problem:
When the rsync task is not running, TOSDaemon uses approximately 1–3% CPU and the CPU package temperature is approximately 52–60°C.
Immediately after starting the rsync task through the TOS GUI, TOSDaemon rises to approximately 194–200% CPU and the CPU temperature rises to approximately 71–78°C.
The rsync process itself uses very little CPU when launched by TOS. I measured the following during the GUI-managed task:
TOSDaemon CPU: 200.5%
rsync CPU: 0.7%
The GUI-generated command includes:
--progress
Example process:
/usr/bin/rsync -rlt --progress --no-o --no-g --no-perms --delete --exclude '#recycle/' --log-file=/Volume1/@rsync/Files_Backup.log --port=873 /Volume1/files/ [email protected]::files/
To isolate the issue, I stopped the GUI task and started the equivalent rsync command manually without the --progress option.
During the manually launched task, I measured:
TOSDaemon CPU: 3.2%
rsync CPU: 39.3%
This indicates that the high CPU usage is not caused by rsync itself or by the file transfer workload. It appears that TOSDaemon is consuming approximately two CPU cores while monitoring or parsing the output from the GUI-managed rsync process, possibly because of the --progress option.
Restarting TOSDaemon temporarily returns CPU usage to normal, but starting the GUI rsync task reproduces the issue immediately.
Steps to reproduce:
1. Create an rsync backup task through the TOS GUI.
2. Start the task.
3. Observe TOSDaemon CPU usage.
4. Stop the GUI task or restart TOSDaemon.
5. Run the equivalent rsync command manually without --progress.
6. Compare TOSDaemon and rsync CPU usage.
Expected behavior:
TOSDaemon should supervise the rsync task without consuming approximately two full CPU cores.
Actual behavior:
TOSDaemon consumes approximately 195–200% CPU for the duration of the GUI-managed rsync task, while the rsync process itself uses less than 1% CPU.
Possible cause:
TOSDaemon may be continuously reading or parsing rsync’s --progress output. Removing --progress from GUI-generated rsync commands, or reducing how frequently progress output is parsed, may resolve the issue.
Please let me know whether any additional diagnostics are needed.
Thank you,