dd命令测试硬盘IO

1.用Linux自带的命令dd测试硬盘IO，如下
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写：

[root@server102 ~]# 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

读：

[root@server102 ~]# 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

 2.第二种方法

[root@dbserver01 email_info]# hdparm -Tt /dev/sda

/dev/sda:
 Timing cached reads:   15854 MB in  2.00 seconds = 7935.60 MB/sec
 Timing buffered disk reads: 1456 MB in  3.01 seconds = 483.98 MB/sec