linux dd命令测试硬盘读写速度

--没有加time命令, 每次写入8k,写640k次，总共5个G大小
[root data1]# dd if=/dev/sda3 of=/data1/test bs=8k count=640K oflag=dsync
655360+0 records in
655360+0 records out
5368709120 bytes (5.4 GB) copied, 210.78 s, 25.5 MB/s




--加上time选项，有详细点的信息
[root ~]# time dd if=/dev/sda3 of=/data1/test bs=8k count=640K oflag=dsync
655360+0 records in
655360+0 records out
5368709120 bytes (5.4 GB) copied, 222.307 s, 24.1 MB/s


real    3m42.309s
user    0m0.578s
sys     1m3.135s