dd命令测试硬盘IO

一,写:

time dd if=/dev/zero bs=1024 count=1000000 of=/tmp/1Gb.file 
1000000+0 records in
1000000+0 records out
1024000000 bytes (1.0 GB) copied, 2.28729 s, 448 MB/s

real    0m2.375s
user    0m0.079s
sys    0m2.028s

二,读:

time dd if=/tmp/1Gb.file bs=64k |dd of=/dev/null 
15625+0 records in
15625+0 records out
1024000000 bytes (1.0 GB) copied, 1.27014 s, 806 MB/s
2000000+0 records in
2000000+0 records out
1024000000 bytes (1.0 GB) copied, 1.27062 s, 806 MB/s

real    0m1.272s
user    0m0.163s
sys    0m1.763s