Explain SMB to Windows Oddities

[mikeyosm]

Hello

 

TR4 2950x

UNRAID: 6.6

10gb local vNIC br0 (mtu 1500)

1gb NIC physical

Win10 VM 1809 (6 cores/12 threads)

SMB Share: Array Disk 1  nvme (contains appdata and downloads share) - Tunable DirectIO set to yes.

 

iperf tests from VM to UNRAID host benched in excess of 10gb/s (no issues there then)

w10 VM nvme drive passed through (benched 3Gb/s)

unraid smb share on nvme drive (benched 2Gb/s)

 

Tests performed:

 

1.) Copy 4Gb file from SMB share to W10 VM (avg 300Mb/s) WHY?

2.) Copy 4Gb (different file) from VM to SMB share (avg 1Gbs/s) Expected.

 

Only copy sessions from SMB to the VM are 50% slower than the other way (VM to SMB share).

 

I also ran iperf tests in both directions:

 

VM to HOST: FAST

 

[  4]   5.00-6.00   sec   261 MBytes  2.18 Gbits/sec
[  6]   5.00-6.00   sec   204 MBytes  1.71 Gbits/sec
[  8]   5.00-6.00   sec   282 MBytes  2.36 Gbits/sec
[ 10]   5.00-6.00   sec   248 MBytes  2.08 Gbits/sec
[ 12]   5.00-6.00   sec   259 MBytes  2.17 Gbits/sec
[ 14]   5.00-6.00   sec   202 MBytes  1.69 Gbits/sec
[ 16]   5.00-6.00   sec   257 MBytes  2.15 Gbits/sec
[ 18]   5.00-6.00   sec   199 MBytes  1.67 Gbits/sec
[ 20]   5.00-6.00   sec   278 MBytes  2.33 Gbits/sec
[ 22]   5.00-6.00   sec   242 MBytes  2.03 Gbits/sec
[SUM]   5.00-6.00   sec  2.37 GBytes  20.4 Gbits/sec

 

HOST to VM: 50% SLOWER than VM to HOST

 

[ 14]   0.00-10.00  sec  1.15 GBytes   990 Mbits/sec   26             sender
[ 14]   0.00-10.00  sec  1.15 GBytes   989 Mbits/sec                  receiver
[ 16]   0.00-10.00  sec  1.10 GBytes   944 Mbits/sec   34             sender
[ 16]   0.00-10.00  sec  1.10 GBytes   943 Mbits/sec                  receiver
[ 18]   0.00-10.00  sec  1.14 GBytes   979 Mbits/sec   26             sender
[ 18]   0.00-10.00  sec  1.14 GBytes   977 Mbits/sec                  receiver
[ 20]   0.00-10.00  sec  1.09 GBytes   936 Mbits/sec   32             sender
[ 20]   0.00-10.00  sec  1.09 GBytes   935 Mbits/sec                  receiver
[ 22]   0.00-10.00  sec  1.12 GBytes   965 Mbits/sec   33             sender
[ 22]   0.00-10.00  sec  1.12 GBytes   964 Mbits/sec                  receiver
[SUM]   0.00-10.00  sec  11.2 GBytes  9.65 Gbits/sec  322             sender
[SUM]   0.00-10.00  sec  11.2 GBytes  9.63 Gbits/sec                  receiver

 

It's like the file transfer from UNRAID to VM is over the 1Gb interface and transfer from VM to UNRAID is over the 10Gb virtual interface br0.

It seems also that If I transfer large files from another SSD in the unassigned devices pool, I don't have any speed issues. Only when transferring between the Array disk and a VM.

 

Any ideas?

 

Edited December 7, 2018 by mikeyosm