# fio --filename=/dev/nvme0n1 --direct=1 --rw=randwrite --bs=4k --ioengine=libaio --iodepth=256 --runtime=60 --numjobs=32 --time_based --group_reporting --name=t --eta-newline=1 --output-format=normal
IOPS=577k  IOPS=576k  IOPS=576k

# mdadm --create --verbose --assume-clean /dev/md0 --level=1 --raid-devices=2 /dev/nvme[0-1]n1
# fio --filename=/dev/md0 ...
IOPS=537k  IOPS=539k  IOPS=538k

# mdadm --detail /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Sat Apr 17 08:49:23 2021
        Raid Level : raid1
        Array Size : 1562681664 (1490.29 GiB 1600.19 GB)
     Used Dev Size : 1562681664 (1490.29 GiB 1600.19 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Sat Apr 17 08:55:08 2021
             State : clean
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : bitmap

              Name : sus-node-4.dc.nazk.gov.ua:0  (local to host sus-node-4.dc.nazk.gov.ua)
              UUID : 83679f2c:7b41e39a:76b16a58:8291f686
            Events : 2

    Number   Major   Minor   RaidDevice State
       0     259        1        0      active sync   /dev/nvme0n1
       1     259        0        1      active sync   /dev/nvme1n1

# mdadm --grow --bitmap=none /dev/md0
# fio --filename=/dev/md0 ...
IOPS=553k  IOPS=554k  IOPS=554k

# vgcreate data /dev/md0
# lvcreate -n simple -l 100%FREE data
# fio --filename=/dev/data/simple ...
IOPS=554k  IOPS=553k  IOPS=555k

# vgremove data
# pvremove /dev/md0
# mdadm -S /dev/md0
# mdadm --zero-superblock /dev/nvme[01]n1

# vgcreate mirror /dev/nvme[0-1]n1
# lvcreate --type raid1 -m 1 --nosync -l 100%FREE -n mirror mirror
# fio --filename=/dev/mirror/mirror ...
obs: 32 (f=32): [w(32)][6.6%][w=626MiB/s][w=160k IOPS][eta 00m:57s]
Jobs: 32 (f=32): [w(32)][8.2%][w=737MiB/s][w=189k IOPS][eta 00m:56s]
Jobs: 32 (f=32): [w(32)][9.8%][w=856MiB/s][w=219k IOPS][eta 00m:55s]
Jobs: 32 (f=32): [w(32)][11.5%][w=977MiB/s][w=250k IOPS][eta 00m:54s]
Jobs: 32 (f=32): [w(32)][13.1%][w=1178MiB/s][w=301k IOPS][eta 00m:53s]
Jobs: 32 (f=32): [w(32)][14.8%][w=1443MiB/s][w=369k IOPS][eta 00m:52s]
Jobs: 32 (f=32): [w(32)][16.4%][w=1672MiB/s][w=428k IOPS][eta 00m:51s]
Jobs: 32 (f=32): [w(32)][18.0%][w=1676MiB/s][w=429k IOPS][eta 00m:50s]
Jobs: 32 (f=32): [w(32)][19.7%][w=1641MiB/s][w=420k IOPS][eta 00m:49s]
Jobs: 32 (f=32): [w(32)][21.3%][w=1671MiB/s][w=428k IOPS][eta 00m:48s]
Jobs: 32 (f=32): [w(32)][23.0%][w=1643MiB/s][w=421k IOPS][eta 00m:47s]
Jobs: 32 (f=32): [w(32)][24.6%][w=1636MiB/s][w=419k IOPS][eta 00m:46s]
Jobs: 32 (f=32): [w(32)][26.2%][w=1637MiB/s][w=419k IOPS][eta 00m:45s]

IOPS=397k  IOPS=388k  IOPS=389k