Slow speeds - ZFS mirror - ESXi host

[tadone]

I'm trying to determine what is the reason for pretty poor write/read speeds to my FreeNas 8.2 virtual machine. My ESXi box is based on a i5 2400S cpu with 16GB of ram. I have allocated 6GB of ram, single cpu and an Intel NIC to FreeNas. It's set up with 2 2TB Green drives mirrored. The drives are attached to a SATA controller (Syba Sil3114 chipset) and passthrough to the FreeNas. I also have "force 4096 sector size" selected.

When I copy large files I get about 10MBps write and about 50MBps read speeds. That seems pretty low to me. I'm on a gig network with a Dell powerconnect switch. Here is what I got with a quick DD test:
953+0 records in
952+0 records out
7985954816 bytes transferred in 408.764595 secs (19536807 bytes/sec)

Is there anything that I"m maybe missing? How can I determine where is the bottleneck? Is it possible that the SATA card is the reason for such low speeds? Any help is appreciated.

 

[Mati2580]

Hi tadone

I see that write speed on hdd is very poor - almost 20 MB/s. Try to change your hdd and test dd once again.

 

[tadone]

I actually figured it out. It was the Syba controller. Once I passed-through my onboard sata controller the speeds improved tremendously. I get around 50MBps write and 100MBps read speeds.

 

[arryo]

So are you using syba controller for datastore? I have the same syba controller and I couldn't make it to work as datastore when I passthrough onboard controller

 

[tadone]

Yes, syba controller is now for my datastore. Make sure you disable passthrough for it and it should work just fine.

 

[arryo]

when I don't passthrough any thing, EXSi booting fine on syba controler, but when I passthrough onboard controller not syba controler, ESXi not recorgnized syba controller anymore. What mainboard are you using?