Using gvfs's smb backend, which uses libsmbclient, forcing encryption usage if available, the transfer speed reduces from around 26-27 MB/s to around 8-9 MB/s.
Is this a server, or a client problem, or a mix of both?
(In reply to Bastien Nocera from comment #0)
Samba 4.7 supports aes hardware encryption on intel compatible hardware.
configure supports --accel-aes=intelaesni
(In reply to Stefan Metzmacher from comment #1)
That helps a fair bit, it's a shame my server doesn't have any acceleration code available though.
starting with 4.11 speed be even better (if hardware supported) as it uses GnuTLS now for encryption. If you have no hardware aes support or if the platform vendor did not submit patches for GnuTLS to support their hardware encryption support (namely IBM for Power and Oracle for Sparc can be mentioned here), then you will still suffer from decreased performance.
If you have a platform with missing GnuTLS HW encryption support, you should file a bug report with the vendors of those platforms; feel free to link that here so we can track improvements.