How to tune Linux kernel for high volume media server?

• From command line (change the device ‘sda’ to appropriate device):

echo “deadline” > /sys/block/sda/queue/scheduler

• kernel parameter, change /boot/grub/menu.lst, add kernel parameter

elevator=deadline

There are two variables which control the behaviour of VM flushing and allocation and affect network and disk performance

• vm.dirty_background_ratio
• vm.dirty_ratio

To set these values from command line

echo 20 > /proc/sys/vm/dirty_background_ratio
echo 60 > /proc/sys/vm/dirty_ratio

to make it permanent, edit /etc/sysctl.conf:

vm.dirty_background_ratio = 20
vm.dirty_ratio = 60

To get current readahead value:

$ blockdev --getra /dev/sda
256

To increase it to a higher value like 16K:

$ blockdev --setra 16384 /dev/sda

Edit /etc/fstab, remove “atime” attribute if there is, add “noatime” attribute.