Slow SMB Copy Speed from Synology to Hard Drive - Gigabit

Posts: 4 · coolspot 2 Jan 2021, 06:18

Hi all,

I have a strange issue with FreeFileSync, it seems to run slowly when trying to sync a large amount of files from a samba share to my computer. With FreeFileSync, I can only get about 30MB/s, but with Windows Explorer (Copy and Paste), I am maxing out the connection at 100MB/s.

Any ideas what can cause FFS to run so much slower? I even upgraded from 10.X version (can't recall what exact release) to 11.4 and the problem persists.

What API does FFS use for Windows File Copy / SAMBA? Is it a custom stack or Windows APIs?

Thanks.

Posts: 3592 · xCSxXenon 12 Feb 2021, 19:02

Something may be 'hijacking' the transmission, I would wager some antivirus

Posts: 4 · coolspot 12 Feb 2021, 19:15

I only have Microsoft Defender and Microsoft Firewall installed. Odd that it will throttle FreeFileSync so significantly in comparison to Windows Explorer.

Perhaps I'll try whitelisting FFS.

Posts: 7050 · Zenju 12 Feb 2021, 19:20

Windows Defender has been the culprit for FreeFileSync slowdowns and server connection issues in the past.

But this should be fixed already by having added FFS to the Windows Defender exclusion list during install: viewtopic.php?t=6312#p20752

Unless Defender has changed the rules in the meantime and it's not longer sufficient (or works differently).