Incompatible combo: Samsung SSD EVO 860 2TB SSD / 2TB with SuperMicro 10DRT-PTR board Workaround: Disable TRIM. You can do this on a system showing symptoms by running this command (takes 10 seconds to complete): echo vfs.zfs.trim.enabled=0 >> /boot/loader.conf && reboot Workaround during install: Also, if you are installing from MEMSTICK and cannot create the ZFS pool due to errors, you can disable TRIM and reboot memstick. [1] During installation, open terminal by typing: ALT-F4. [2] Mount the USB stick rw: mount -u -o rw / [3] and then edit the loader.conf on the USB stick: echo vfs.zfs.trim.enabled=0 >> /boot/loader.conf && reboot Info on disks: # camcontrol devlist <Samsung SSD 860 DCT 1.92TB HXT70B6Q> at scbus5 target 0 lun 0 (pass1,ada0) <Samsung SSD 860 DCT 1.92TB HXT70B6Q> at scbus6 target 0 lun 0 (pass2,ada1) Info on Motherboard from dmidecode: Supermicro, X10DRT-PTR Errors logs: Jan 15 07:23:31 dosa-b kernel: ahcich4: Timeout on slot 7 port 0 Jan 15 07:23:31 dosa-b kernel: ahcich4: is 00000000 cs 00000000 ss 00000000 rs 00000080 tfd 40 serr 00000000 cmd 0004c717 Jan 15 07:23:31 dosa-b kernel: (ada0:ahcich4:0:0:0): SEND_FPDMA_QUEUED DATA SET MANAGEMENT. ACB: 64 01 00 00 00 40 00 00 00 00 00 00 Jan 15 07:23:31 dosa-b kernel: ahcich5: (ada0:ahcich4:0:0:0): CAM status: Command timeout Jan 15 07:23:31 dosa-b kernel: (ada0:ahcich4:0:0:0): Retrying command, 3 more tries remain Jan 15 07:23:31 dosa-b kernel: Timeout on slot 8 port 0 Jan 15 07:23:31 dosa-b kernel: ahcich5: is 00000000 cs 00000000 ss 00000000 rs 00000100 tfd 40 serr 00000000 cmd 0004c817 Jan 15 07:23:31 dosa-b kernel: (ada1:ahcich5:0:0:0): SEND_FPDMA_QUEUED DATA SET MANAGEMENT. ACB: 64 01 00 00 00 40 00 00 00 00 00 00 Jan 15 07:23:31 dosa-b kernel: (ada1:ahcich5:0:0:0): CAM status: Command timeout Jan 15 07:23:31 dosa-b kernel: (ada1:ahcich5:0:0:0): Retrying command, 3 more tries remain