hdparm -t --direct /dev/sda

dd if=/dev/sda of=/dev/null bs=1M

Write (10GB File):

# dd if=/dev/zero of=erase.bin bs=1M count=10000

Read (10GB File):

# dd if=erase.bin of=/dev/null bs=1M count=10000
# rm erase.bin

fio --ioengine=libaio --filename=/filenameorblockdevice --direct=1 --sync=1 --rw=write --bs=4M --numjobs=1 --iodepth=1 --runtime=600 --time_based --group_reporting --name=fio-disk --output-format=terse,json,normal --output=fio.log --bandwidth-log

fio --filename=/file --direct=1 --fsync=1 --rw=randwrite --bs=4k --numjobs=1 --iodepth=1 --runtime=60 --time_based --group-reporting --name=4k-sync-write-test

^{ARM 1.6GHz + WD Green}
Write 10485760000 bytes (10 GB) copied, 143.207 s, 73.2 MB/s
Read 10485760000 bytes (10 GB) copied, 130.184 s, 95.8 MB/s

^{ARM 1.6GHz + USB3.0 External HDD}
Read and Write, 71/71 MB/s (ntfs)

^{Raspberry PI4 + USB3.0 External SDD}
Read and Write, 358/217 MB/s (ext4)

Sequential Read: 205 MB/s, Write: 69 MB/s
Random Read: 12 MB/s (3300 IOPS 4KB), Write: 9 MB/s (2348 IOPS 4KB)

Sequential Read: 214 MB/s, Write: 143 MB/s
Random Read: 17 MB/s (4567 IOPS 4KB), Write: 12 MB/s (3181 IOPS 4KB)