Simple dd command to test HDD read/write performance under linux

Simple dd command to test HDD read/write performance under linux    2021/02/22 update

Read

#dd oflag=direct if=/dev/zero of=/mnt/test bs=512k count=20000

Write

#dd iflag=direct if=/mnt/test of=/dev/null bs=512k count=20000

If you want to test different disk, you can mount /mnt to diffect /dev/sdx

#mkfs -t ext4 /dev/sdb1

#mount /dev/sdb1 /mnt

Another way:

Write

time dd if=/dev/zero of=test.dbf bs=512k count=20000

real 0m36.669s

user 0m0.185s

sys 0m9.340s

8*300000/1024/36.669=63.916M/s

Read

time dd if=/dev/sda1 of=/dev/null bs=512k count=20000

real 0m51.070s

user 0m0.054s

sys 0m10.028s

8*448494/1024/51.070=68.61M/s