Negatives of syncthing in my testings so far

  1. Syncthing uses at least 10% CPU regardless of things to sync, or if it’s all up to date. Usually it’s around 20-30% if there is stuff to sync.

  2. It goes incredibly slow (kbps instead of mbps) on local LAN. Is this normal? Is there a way to kick it up a notch and use the gigabit bandwidth available throughout my home?

  3. I can’t seem to get a connection over the WAN to sync with all three of my LAN PCs. It will connect with my QNAP, but it does not connect with either of my other windows boxes. WAN PC is also windows.

I love the layout and information available via syncthing’s layout, especially using syncTrayzor. But the speed is a serious issue and the CPU load bother’s me a bit… however, if I can’t get all the devices to connect (they stay “disconnected”) then it seems a bit pointless. Thoughts?

  1. if everything is up to date it should be really low, do you have many files and a low rescan interval? Try increasing it to see if it helps. To still detect changes fast you can use then.

  2. probably limited by the CPU of the weaker device, hashing and encryption needs a lot of CPU. If it’s the CPU you can’t do much about it… see

  3. do you use manual port forwarding or UPnP? For manual forwarding you could show the setting of the router, for UPnP I have no idea what you can do there if one device works but the others not, maybe setting the environment variable STTRACE=upnp can give you more information in the log then.

Using this and SyncTrayzor together will go badly, and there’s no need to anyway since SyncTrayzor does its own filesystem watching.

That shouldn’t be the case: my Syncthing CPU usage is so low it’s lost in the noise. Is it scanning? Set ‘STTRACE=model,scanner’ in the ‘Syncthing Environmental Variables’ section, in ‘Settings -> Syncthing -> Advanced’. Syncthing tell you about what it’s doing

No. See if the side you’re syncing to is maxing out its CPU.

Can both PCs find the discovery server? Is the WAN PC behind a NAT device? If so, has at least one side managed to get a UPnP mapping?

At first I had two windows PCs with strong processors (Dual Xeon in one, and new i7 in the other) on the same gigabit network and the speed was still abysmal. CPU was around 20-30% at the time… I’ve never checked after a sync, but it’s been days and the sync is still processing between the four devices (3 windows PCs with good processors and the latest, a QNAP with an x86 processor. I know that’s the weakest link, but the speed between computers was ridiculously slow before I added the qnap. I thought things might speed up after I started adding more devices… nope. Silly thought, but hopeful.

If it’s a CPU limitation for speed, shouldn’t it still go fast between strong CPU PCs? Because that too is still in the kbps… pretty strange.