CentOS 7 tuned profile for redis

Redis might spill a few warnings about transparent hugepages, overcommit memory or tcp backlog during startup depending on your OS and redis configuration. Instead of fiddling with /etc/sysctl.conf, kernel line /etc/grub.d/00_derp.conf and /etc/rc.local and whatnot, you can use a tuned profile to fix all of those.

Check the current active profile, which is virtual-guest in this example.

cat /etc/tuned/active_profile
virtual-guest

Create a new profile for redis

mkdir /etc/tuned/hurr-durr-redis

Copy the current active profile from /usr/lib/tuned/virtual-guest/tuned.conf

cp /usr/lib/tuned/virtual-guest/tuned.conf /etc/tuned/hurr-durr-redis/

Edit the /etc/tuned/hurr-durr-redis/tuned.conf and add the blocks and/or lines depending on what warnings you got.

[main]
include=throughput-performance

[vm]
# Redis : WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis.
# Fix by disabling THP
transparent_hugepages=never

[sysctl]
# Copied from 'virtual-guest' in /usr/lib/tuned/virtual-guest/tuned.conf
vm.dirty_ratio = 30
vm.swappiness = 30

# Redis : WARNING overcommit_memory is set to 0! Background save may fail under low memory condition.
# Fix by enabling vm.covercommit_memory
vm.overcommit_memory = 1

# Redis : WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128
# Fix by setting somaxconn value over 511
net.core.somaxconn = 512

Reload tuned.service (might not be necessary)

systemctl reload tuned.service

List all profiles and you should see your new redis profile in the list.

tuned-adm list

Set the new profile as active

tuned-adm profile hurr-durr-redis

And restart redis

systemctl restart redis.service

Update 2018-04-30 tuned version and After

Thank you Mufit Eribol for pointing out that on reboot tuned profile was not applied in time. Extend redis.service configuration with following snippet in /etc/systemd/system/redis.service.d/after_tuned.conf.

[Unit]
After=tuned.service

An issue on Github also affects this setup as CentOS 7 @updates has tuned 2.8. In order to update tuned to version 2.9 you need to enable continous release repository.

Hopefully no more warnings :)