I’ve been using urbackup for a while and am now on the latest server version, 2.5.33.0-1 and client for windows. Had to download the binary and manually install but that’s another thread. 
I have noticed that on a large backup for a local Windows 11 client the backup stops after about 33% of a 2TB drive, which is at ~750G full. It just hangs. I decided to see if it starts again and it didn’t after a couple hours. I started a ping from the client to the server and almost immediately the backup restarted at about 700Mbit/s. Just thought I would pass this along. I’m using a new server version and hadn’t seen this before. I don’t recall my old server version and have retired that server but could try to figure it out if anyone is interested. I just wanted to let people know that a ping restarted the backup! The other windows machines are working fine but don’t have as large of a disk. Just an FYI to help.
Well, got to 76% and now it isn’t responding again, all on the local network. I’m stumped, I think there’s a 50% chance it will restart again but who knows. Looks like I’m also suffering from the client pauses. I disabled, that helped as well.
I have got used to the backup taking ages, so just learn to ignore it. The main thing I check is the “Activity” page and watch if the file count is still moving.
Daft things to check…
- Multiple backups to the same server running at the same time slow things right down. Try and stagger backup times.
- Replace the network leads. Sometimes you just don’t see how broken that old lead is.
- Check state of old network switches, swap to different port.
My backup server is on really old hardware, but the network around it is fast. A backup can take ages for me, but always gets there in the end.
This is multiple OS versions (Win7, Win10, Unraid Linux) backing up to an Unraid Linux box. I also have Win11 systems backing up to Win10 at other locations.
The behavior seems different than my old server but I have to agree. It stops backing up for 20-30 min then starts again like gang busters, doesn’t show paused anymore as I took that client option away. I don’t recall that happening on my old server but then again I wasn’t looking at it very often as I am with the new one right now.
As with anythiung in IT with a progress bar, if you start watching, the “Kettle Mode” algoithm kicks in. “Watched Kettle Mode” then slows down time and will not progress while it is being watched. You need to turn away and do something else. 
When I watch my first backups of new data I am sure they are extra slow too. But I think it is just Kettle Mode. So walked away and did something more interesting.
Worst feature of Kettle Mode is the time it takes between 98% and 100%. That time can usally be longer than the whole backup…