Copiers & Puller Max Pending Ki B

I realize this is a loaded question, but how would I go about improving the transfer rates? Here is some baseline information. I am using a Synology 2 disk NAS in RAID 1 with WD Red Drives. Everything is Gigabit over Cat5E. MTU is set to 1500.

I have my Copiers set to 0, and Puller Max Pending Ki B set to 8192. This is for both source and destination of SyncThing.

I don’t fully understand the significance of the settings in both locations. I suppose those settings are for bi-directional transfers? In my use case my source is “read-only” and my destination is “write-only”.

It depends a lot on the size of files as well. You can consider that each file has a fairly expensive overhead which, if the files are small, dominates everything else. Especially on rotating disks. But apart from that, rough guidelines;

  • “Copiers” adjusts how many parallell threads are used to copy file data, which is the initial step of syncing files. The default (which is used when you set it to zero) is two. This is fine in most setups and probably won’t affect your transfer rate.

  • “Puller pending KiB” is how much data we can request and have “in flight” over the network at any given time. Larger values compensate for higher latency networks (and disks, to some extent). If you’re syncing over a LAN it probably doesn’t matter much. The minimum value at the moment is actually 16384 so your setting will get adjusted upwards at runtime.

Both of these settings matter / take effect on the receiving side only.

If you have millions of kilobyte-sized files none of them will matter at all and you will have a life of suffering.

Thank you for the explanation. I will tinker. :grinning:

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