The Read performance of a Disk can be improved by increasing a parameter called "Read+Ahead" using 'blockdev' command. By default the Linux OS will read 128 KB of data in advance so that it is already in Memory cache before the program needs it. This value can be increased so as to get better Read Performance.
Steps to check and increase the Read-Ahead value:
To check the current 'blockdev' status of all block device: # blockdev --report
[root@linuxserver ~]# blockdev --report
RO RA SSZ BSZ StartSec Size Device
rw 16384 512 4096 0 14680064 /dev/sda
rw 16384 512 1024 63 208782 /dev/sda1
rw 16384 512 512 208845 10265535 /dev/sda2
rw 16384 512 4096 0 2147483648 /dev/sdb
rw 16384 512 4096 0 35651584 /dev/sdc
rw 16384 512 2048 63 35648172 /dev/sdc1
rw 16384 512 4096 0 104857600 /dev/sdd
To check the 'Read-Ahead' value of an individual disk (let's take sda)
# blockdev --getra /dev/sda
(or)
# cat /sys/block/sda/queue/read_ahead_kb
To change the 'Read-Ahead' value to 8 MB (16384 times of 512 bytes blocks).
# blockdev --setra 16384 /dev/sda
To make it permanent upon system reboot, just add this command entry in /etc/rc.local.