yes, if we can have some more data it would be better, randomly
google the "dd" performance, someone said below:
https://stackoverflow.com/questions/33485108/why-is-dd-with-the-direct-o-...
Above is for directio, seems sync io is different, anyway with below
test on laptop, it seems directio is faster:
[dyoung]$ dd if=/dev/zero of=testfile bs=1M count=100 oflag=direct
100+0 records in
100+0 records out
104857600 bytes (105 MB, 100 MiB) copied, 0.202895 s, 517 MB/s
[dyoung]$ dd if=/dev/zero of=testfile bs=1M count=100 oflag=sync
100+0 records in
100+0 records out
104857600 bytes (105 MB, 100 MiB) copied, 1.13316 s, 92.5 MB/s