[CentOS] Very slow disk I/O

Hi Users

I am using RHEL 6.5 on my server.

From top command i can see that the processors in my server are spending a lot of time on wait for I/O. I can see high percentage in terms of 30-50% on "wa" time.

Here is the df output about the disk space in my system:

********** [root@localhost images]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 1915071844 103227908 1714563936 6% / tmpfs 32931472 0 32931472 0% /dev/shm **********

Could someone point me on how to improve the disk I/O on my server and reduce the wait time on I/O.

Thanks Jatin