Need a guide /help installing memcached on LAMP to improve performance

OliverJ 2020-12-13 12:48:03 UTC #1

Keywords: LAMP/MAMP/WAMP - Google Cloud Platform - How to - Other
Description:
I am trying to install memcached, there is mention of it here on this page: https://docs.bitnami.com/virtual-machine/faq/administration/improve-server-performance/

However, the resource it points to does not make mention of memcached.

I would like to install it. I followed the steps here:

I think I need to configure either memcached or php and mysql to use the cache, and I'm not even sure it is installed in the right directory. Per that guide, memcached config file can be found at /etc/memcached.conf

Thanks

OliverJ 2020-12-13 15:52:54 UTC #2

OK, update:

I found this guide here: https://docs.bitnami.com/general/apps/wordpress/configuration/install-modules-php/#memcached-using-libmemcached

But it ends with the following error when I invoke "make":
...
CXX clients/memflush.o
clients/memflush.cc: In function ‘int main(int, char**)’:
clients/memflush.cc:42:22: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
if (opt_servers == false)
^~~~~
clients/memflush.cc:51:24: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
if (opt_servers == false)
^~~~~
make[1]: *** [Makefile:5832: clients/memflush.o] Error 1
make[1]: Leaving directory '/tmp/libmemcached-1.0.18'
make: *** [Makefile:3700: all] Error 2

I tried a different source to wget : https://launchpad.net/libmemcached/1.0/1.0.18/+download/libmemcached-1.0.18.tar.gz
but that also failed.
Then I tried an older version:
https://launchpad.net/libmemcached/1.0/1.0.17/+download/libmemcached-1.0.17.tar.gz

Then I found this post:

And I tried the suggested:
sudo apt install libmemcached-dev

Seemed to install fine.

I uncommented this line in httpd.conf:
LoadModule socache_memcache_module modules/mod_socache_memcache.so

I added this to php.ini:
extension=memcached.so

Then I restarted php / apache etc with:
sudo /opt/bitnami/ctlscript.sh restart

To test I used your page here: https://docs.bitnami.com/google-templates/infrastructure/memcached/troubleshooting/test-memcached/

And these seems to be working now. I also have the memcached appearing in the output of phpinfo();

I followed the rest of the instructions on your wordpress memcached guide, but not all succesfully:
this command failed:
mv /opt/bitnami/memcached/scripts/ctl.sh.disabled /opt/bitnami/memcached/scripts/ctl.sh
sudo /opt/bitnami/ctlscript.sh start memcached

not surprising - I'm not sure where memcached has installed, and it isn't in the bitnami directory....

I will have to make do with using commands outside of the bitnami control script to control memcached for the time being ... and make sure that memcached starts when the machine is restarted!

I next need to figure out how to configure Wordpress to use memcached. Your wordpress guide didn't go into that detail, which I found odd.

gongomgra 2020-12-14 10:39:39 UTC #3

Hi @OliverJ,

Thanks for posting your question. The link on how to install Memcached on Debian 9 helps you to install Memcached using the system packages (apt-get install memcached...), so it won't be located in the /opt/bitnami/memcached directory and the other commands won't work. Can you also share the link to the guide you mention to enable the ctl.sh script for Memcached so we can check it?

Apart from that, I understand you need to use a WordPress plugin to use Memcached with your website. Can you check if that plugin works for you?

OliverJ 2020-12-14 10:59:39 UTC #4

HI,

OK - thanks. The ctl.sh was in my first link on the bitnami module installations for wordpress: https://docs.bitnami.com/general/apps/wordpress/configuration/install-modules-php/#memcached-using-libmemcached

I didn't use that plugin, I found a suitable wordpress plugin in the end which was Memcached Redux available here:

After installing a stackdriver extension I was able to monitor Memcached in action through google cloud monitoring, so it looked like that all worked.

Do you know how to add the memcached system package control to the bitnami control script and/or how to make sure that it is loaded and running at boot?

Cheers

michiel 2020-12-15 11:53:11 UTC #5

Hi @OliverJ,

You could add the command for starting the memcached daemon to the /etc/init.d/bitnami file.

Regards,
Michiel

OliverJ 2020-12-22 11:11:40 UTC #6

Cheers - I went with:

sudo systemctl enable memcached.service

system 2021-01-05 11:11:47 UTC #7

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