Not getting high 10Gb speed in mirror pool

[zookeeper21]

I have 8 HDD in group of 4 with each having 2 disk in mirror (Total 4 vdev). I am getting write speed of around 250Mb/S and read is around same. I believe it should be more than that. I also have 2 SSD in another pool in mirror and I was getting 458Mb/S read but after changing MTU to 9000, I started getting 760Mb/S, but nothing changed for HHD Disk pool.
Anything else can be done?

 

[rvassar]

Should be a bit more than that... But you have a couple things working against you. You need more RAM... 8Gb is the bare minimum. You likely don't have a big enough ARC to cover the 16Tb pool, and are also starving the OS for buffer space to keep all the transfer queues supplied. I'm also wondering about the specs on that CPU supporting that many PCIe lanes. You may have some subtle architectural issue hidden in that combo that isn't immediately obvious.

 

[zookeeper21]

@rvassar I though CPU I am using is more powerful than what IXsystems using their system they sell. I though having 8 Disk in that setup should be good enough but I will buy more RAM and see if it affects anything.