low disk write speed

[shuicc8493]

Hi
I am running the truenas 12.0U8 version on a server with the following hardware :
CPU: Intel(R) Xeon(R) Platinum 8163 CPU @ 2.50GHz
Memory： DDR4，32G，2666MHz，ECC
Disk： Samsung SSD 870 EVO 1TB
FreeNAS: 12.0-U8
I create a zpool with the Samsung SSD disk in strip mode with only data vdev, and create a directory on the zpool, then I test the speed with dd command, but the write speed is very slow.
the dd command is "dd if=/dev/urandom of=./1.file bs=1M count=10000 oflag=direct "
the following picture is the disk write speed acquired by " systat -iostat -numbers 1" command

ada2 is Samsung SSD disk. But if the disk is moved to another server with Centos system , after formated with ext4 filesystem , it can achieve about 400M bytes write speed.
So why the same SSD is so slow in truenas? if some extra settings should be set?

 

[sretalla]

using /dev/random as an input puts the task on your CPU... typically that's a really bad way to find out how fast your disks can go.

Use that file as the input (from another pool) ... right after having read it out a few times to /dev/null to make sure it's in ARC... then try it to the pool you want to test.