[root@iZ25oat874uZ data]# time dd if=/dev/zero of=/var/test bs=8k count=1000000
1000000+0 records in
1000000+0 records out
8192000000 bytes (8.2 GB) copied, 114.885 s, 71.3 MB/s
real 1m54.947s
user 0m0.185s
sys 0m9.719s
[root@iZ25oat874uZ data]# time dd if=/dev/zero of=/var/test bs=8k count=1000000
1000000+0 records in
1000000+0 records out
8192000000 bytes (8.2 GB) copied, 114.885 s, 71.3 MB/s
real 1m54.947s
user 0m0.185s
sys 0m9.719s