Recommended Redis installation, manage and maintain Redis through SSH

Hello @carsten-lund

Thank you for reaching out and I am happy to help.
W3 Total Cache recogizes the Php extension so the important thing is to install phpredis in order to be able to use it via W3 Total Cache.

• Make sure that the redis server is accessible from the web application servers
  • Redis installation instructions: https://redis.io/topics/quickstart
  • If installing redis on a dedicated server, make sure that the web application servers have access to TCP Port 6379
  • Add the following at the end of your?/etc/redis/redis.conf?config filemaxmemory 2048mb # This should be 50% of your available RAM in the node maxmemory-policy allkeys-lru

You can also check these installation instructions if you find it easier,

and for the memory change please check this link for more details.

I hope this helps!

Thanks for your answers and links. Its getting a bit too complicated I think, so I’m considering installing Redis trough an image in Docker instead, where I can update and change memory though panel settings instead.

Do you have a link or a command for uninstalling the existing Redis installation from server through SSH first?

Hello @carsten-lund

Thank you for your feedback.
Please check this link for more information on how to uninstall redis using the command line.

Thanks!

Hi Marko, thank you very much, I haven’t been able to find this usefull information.

One more question. I activated object cache in W3TC, and the test passed: Redis hostname:port / IP:port: 127.0.0.1:6379

But if I check the Query Monitor, there is no object caching?

Regards

Hello @carsten-lund

I am guessing that you are checking this while looged in?

Can you please share your website URl?

Thanks!

muii.dk

I’m attempting to remove the server, with no luck, but I must admit that I don’t know what I’m doing ??

:~/redis-stable# sudo apt-get purge --auto-remove redis-server
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package 'redis-server' is not installed, so not removed
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.

:~/redis-stable#  sudo rm /etc/redis/redis.conf
rm: cannot remove '/etc/redis/redis.conf': No such file or directory

• This reply was modified 1 year, 9 months ago by Carsten Lund.
• This reply was modified 1 year, 9 months ago by Carsten Lund.

Hello @carsten-lund

can you please shwhich hosting provider you are hosing the website on- which platform you are using?

Thanks

Hello, it’s a VPS S NVMe server on Contabo, OS Ubuntu 20.04.5 LTS

Apparently it should be uninstalled, but I’m not able to run the Redis image from Docker.

~# apt-cache policy redis-server
redis-server:
  Installed: (none)
  Candidate: 5:5.0.7-2ubuntu0.1
  Version table:
     5:5.0.7-2ubuntu0.1 500
        500 https://asi-fs-d.contabo.net/ubuntu focal-updates/universe amd64 Packages
        500 https://security.ubuntu.com/ubuntu focal-security/universe amd64 Packages
     5:5.0.7-2 500
        500 https://asi-fs-d.contabo.net/ubuntu focal/universe amd64 Packages
  

If I use Automatic port mapping: Object caching via redis is currently enabled

But if I choose Manual mapping?6379?to external?6379, I receive the address already in use error, so apperantly not all of the old Redis installation has been removed from server.

{“message”:”driver failed programming external connectivity on endpoint redis (2151b9d53ad0df37ccf5369ad19c153760e32bd7f57ede713211c4edc2ffce5a): Error starting userland proxy: listen tcp4 0.0.0.0:6379: bind: address already in use”}

Should port 6379 always be used?

Hello @carsten-lund

Thank you for your feedback. Have you tried checking this with your hosting support (This is not directly related to the W3 Total Cache)

Also, are you still using the Redis Object Cache plugin for this?

Thanks!

Hi Marco, thanks for helping out, though I know it’s not in the scope for W3TC.

Apparently it is working now, when I stop the Redis container in Docker, the status in the plugin is “not connected”, so I guess that means that it is the Redis image which is in use, not the manually installed version anymore.

Thanks

• This reply was modified 1 year, 9 months ago by Carsten Lund.

Hello @carsten-lund

Thank you for your feedback.

Yes, it appears so since the W3 Total cache only recognizes the PHP extension of the module.

Thanks!