Performance discrepancy on Windows share

[philsh]

I am new to TrueNAS. I have a server set up with latest CORE version. It is a Dell R720 with an MD1280 attached. I created a pool with three vdevs - each has 14 8TB drives. I created a Windows share on it. Here is my problem. If I map the drive on Windows Server and then copy a large file using Windows explorer, the speed seems good: about 400MB/second. However, if I copy the same file using Robocopy in powershell, the speed is about 10% of the above. I also tried running a Veeam backup and store into this share. The best speed it gets is 183 MB/sec and Veeam reports the bottleneck is the target drive.

Is there some settings I am missing? I would appreciate any ideas. Thanks.

[winnielinnie]

Perhaps related?

Lower than expected network transfer speeds - robocopy

Ok so I have worked it out. Following your guidance it logically meant that the issue is with the robocopy command itself and not the hardware or TrueNAS. After 2 min of research I found that removing the restartable switch (/z) increased the throughput from 58Mb/s to nearly 2000Mb/s (2Gb/s). Amazing improvement. I thought for future readers this may be important. Thanks again for your help, much appreciated as I wouldn’t have probably worked that out myself.

[philsh]

Wow. That fixed it for robocopy. Interesting. Thank you!