Slow copy on Mac over SMB/VPN

[cjdshaw]

I'm accessing my work server over an SMB share, via Pulse Secure VPN on Mac OSX 10.14.6 with a 200Mbps downlink. Just dragging a file in Finder, I get about 5MB/s. Using FFS on my Windows PC is about the same.

But using FFS on the Mac, it drops to 2.5MB/s at best, and more usually 1.5MB/s

I've tried with and without Fail-safe copy, but that doesn't seem to make a difference. The FFS graph also seems very "bursty" with sharp climbs where it reads 20MB/s, then a plateau where it reads 0

Using FFS on the local network with the Mac is fine, with 25Mb/s comfortably to my SMB NAS

Can anyone advise, or is there any debugging I can do?

[xCSxXenon]

I wonder if the plateau you are seeing is a buffer being filled up, then 0 while it empties it to disk

[cjdshaw]

I wonder if the plateau you are seeing is a buffer being filled up, then 0 while it empties it to disk

That does sound right. Any tips on what I could do about it? It’s clearly fine at the OS level, and I can’t find a FFS buffer setting

[cjdshaw]

Any more thoughts on how I might fix this? My SSD has a write speed of 1500Mb/s, so any buffer flushes ought to be near instantaneous