我有两台服务器，一台带有 SSD，一台带有 HDD。我一直在运行 hdparm 来查看差异，但是 Timing cached reading 和 Timing 的结果相当相等/HDD 更快：
固态硬盘：
Timing cached reads: 26080 MB in 2.00 seconds = 13053.64 MB/sec
Timing buffered disk reads: 1558 MB in 3.00 seconds = 518.77 MB/sec
Timing O_DIRECT cached reads: 966 MB in 2.00 seconds = 482.99 MB/sec
Timing O_DIRECT disk reads: 1528 MB in 3.00 seconds = 508.71 MB/sec
硬盘：
Timing cached reads: 28248 MB in 2.00 seconds = 14137.88 MB/sec
Timing buffered disk reads: 496 MB in 3.01 …