Syncthing and initial scans (slowing down my drive)

Hi there,

I’m not sure if any of this is possible, I tried search but I’m really looking to kill Syncthing’s initial scan on boot. I have the watcher on and that works amazingly. I have rescan interval on 0 to disable the rescanning.


  1. I “assume” (bold move, I know) this kills my hard drive(s).
  2. It peakes my drive to 100% use for a solid while. When playing games/doing I/O intensive stuff on the same drive where Syncthing dirs are, it’s insanely slow while this scan is running.

My stats: 993,647 files, 103,452 directories ~586.49GiB

If I’m asking the wrong question (or I’m being insane!) and you have suggestions to help me out, feel free to leave those below too!


Yes, it does this, sadly there is no way to prevent this. We know this is an issue, and there is already a ticket for this.

Thanks for your response. Do you have any recommendation on what to do and is it possible I can follow said ticket? I really love the procut but this is slowly becoming a deal breaker for me.

If you have this problem on a computer where you can do gaming, then there is something wrong. I have 178,352 files, 15,732 dirs and ~428GB on a old thinkpad x220 and there is a short period of slight slowness after startup, but neither very hindering nor long. You have quite a bit more files/dirs, but not that much, so it shouldn’t be much worse. I.e. what I am saying is, that I would investigate why the initial scan takes so long, maybe the disk is dying?

@imsodin it’s all relative to how many folders you have on the same spindle, as the initial scans kick off all at the same time, so with 10 folders on the same spindle, 4 threads per folder (num cores), and actual changes in those foldeers, you’d end up thrashing the disk.

I have 7 shared folders on 1 disk. All the stats I listed in my OP is a summary of all of them.

Processing power isn’t an issue but my games are located on the same disk as my shared folders. The I/O that the initial scan does is so intensive on the disk that loading games is insanely slow during initial scan (Windows’ task manager shows the disk activity being at a 100%).

If I reboot 3 times a day, I’m fairly sure my disk’s health wouldn’t be too good after all that scanning.

If the content has not changed in the folders, it should not be an issue. Yet from your screenshot, your disk doesn’t look healthy with 300kb read speeds.

It’s indeed not being changed on reboot. It just seems to be the initial scan.

I’m not sure what Windows counts as read speed. Without Syncthing open my speeds are just fine.

Scanning folders if nothing is changed pretty much does not read any data, as it just checks the filesystem index for modification timestamps etc. So I’d verify that its not reading and data.

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