Redis Server installation FAQs

OS: CentOS 7 Minimal

(0) open files

Q: Increased maximum number of open files to 10032 (it was originally set to 1024).
A:

$ulimit -a
$vi /etc/systemd/system/redis.service

In the "[Service]" unit, add the following:

LimitNOFILE=

(1) somaxconn
Q: WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.

A:
$vi /etc/sysctl.conf

net.core.somaxconn=

(2) overcommit_memory
Q: WARNING overcommit_memory is set to 0! Background save may fail under low memory condition.
To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1'
for this to take effect.

A:

$echo "vm.overcommit_memory=1" > /etc/sysctl.conf
$reboot
$ > /proc/sys/vm/overcommit_memory

(3) thp disable
Q: WARNING you have Transparent Huge Pages (THP) support enabled in your kernel.
This will create latency and memory usage issues with Redis.
To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root,
and add it to your /etc/rc.local in order to retain the setting after a reboot.
Redis must be restarted after THP is disabled.

A:

reference: https://www.centos.org/forums/viewtopic.php?t=49428

$vi /etc/rc.d/rc.local

echo never > /sys/kernel/mm/transparent_hugepage/enabled
echo never > /sys/kernel/mm/transparent_hugepage/defrag

$chmod +x /etc/rc.d/rc.local

redis.log

:M  Sep ::36.921 # User requested shutdown...
:M  Sep ::36.921 * Saving the final RDB snapshot before exiting.
:M  Sep ::36.927 * DB saved on disk
:M  Sep ::36.927 * Removing the pid file.
:M  Sep ::36.928 # Redis is now ready to exit, bye bye...
:C  Sep ::07.493 # systemd supervision requested, but NOTIFY_SOCKET not found
                _._
           _.-``__ ''-._
      _.-``    `.  `_.   (/)  bit
  .-`` .-```.  ```\/    _.,_ ''-._
 (    '      ,       .-`  | `,    )     Running in standalone mode
 |`-._`-...-` __...-.``-._|
 |    `-._   `._    /     _.-'    |     PID: 981
  `-._    `-._  `-./  _.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |           http://redis.io
  `-._    `-._`-.__.-'_.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |
  `-._    `-._`-.__.-'_.-'    _.-'
      `-._    `-.__.-'    _.-'
          `-._        _.-'
              `-.__.-'                                               

:M  Sep ::
:M  Sep ::07.545 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
:M  Sep ::07.550 * DB loaded from disk: 0.005 seconds
:M  Sep ::
:M  Sep ::47.949 # User requested shutdown...
:M  Sep ::47.949 * Saving the final RDB snapshot before exiting.
:M  Sep ::47.964 * DB saved on disk
:M  Sep ::47.964 * Removing the pid file.
:M  Sep ::47.965 # Redis is now ready to exit, bye bye...
:C  Sep ::18.272 # systemd supervision requested, but NOTIFY_SOCKET not found
                _._
           _.-``__ ''-._
      _.-``    `.  `_.   (/)  bit
  .-`` .-```.  ```\/    _.,_ ''-._
 (    '      ,       .-`  | `,    )     Running in standalone mode
 |`-._`-...-` __...-.``-._|
 |    `-._   `._    /     _.-'    |     PID: 978
  `-._    `-._  `-./  _.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |           http://redis.io
  `-._    `-._`-.__.-'_.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |
  `-._    `-._`-.__.-'_.-'    _.-'
      `-._    `-.__.-'    _.-'
          `-._        _.-'
              `-.__.-'                                               

:M  Sep ::
:M  Sep ::18.361 * DB loaded from disk: 0.007 seconds
:M  Sep ::

/var/log/redis.log