Improving disk I/O reads (Linux)

Our SAN is optimized for random IO as that is more typical in a hosting environment. Enabling readahead under Linux will greatly increase sequential reads. 

 

blockdev --setra 16384 /dev/xvda1

 

Replace /dev/xvda1 with /dev/sda1 on older distributions.  You can add this command to /etc/rc.local to make it persistent across reboots.