iSCSI slower than SMB and NFS

warriorcookie

Explorer
Joined
Apr 17, 2017
Messages
67
Sorry, I know there's been so much posted on this subject. Frankly my head is spinning and I could use some guidance to help narrow down what's causing the issue in my specific case.

System details in my sig below.

I have a Windows 10 VM (VMXNET3 NIC) on the same host as my FreeNAS VM (vmware E1000 NIC).
I'd like to have a program files drive for windows that's hosted by FreeNAS. It'll have some games, CAD software, etc.

When connecting to my iSCSI zvol and doing a file transfer the write speeds are extremely unstable, bouncing up and down between 50MB/s and 125MB/s.
Using SMB, the write speeds bounce between 150MB/s and 180MB/s
NFS with sync=disabled speeds are pretty steady at 185MB/s

I have 4 threads of a E5-2667 v2 dedicated to FreeNAS VM and the usage hits 25% with iSCSI.

Read speeds are a bit slower than expected too, but I can live with them. iSCSI - 185MB/s vs SMB - 250MB/s
 
Last edited:

warriorcookie

Explorer
Joined
Apr 17, 2017
Messages
67
So I upgraded the E1000 virtual NIC in my FreeNAS install to VMXNET3 and enabled tro and lro. Made a world of difference. iscsi is now 250-300MB/s and SMB is around 350MB/s just doing a file copy from NVMe C: to the network shares.
Using Crystal DiskMark the gap narrows even more.

I'm happy for now, but maybe I'll experiment a bit more with sync disabled or cacheing.

If anyone else has any suggestions I can further tune this with please suggest away.
 
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