Questions[php-memcached](server)

I've always installed apcu and memcached on my server, but I'm not sure how useful they are. Mostly 2-3 pages per visit are visited on my sites. And I'm not even sure if having them is a good thing or a bad thing, whether it's talking about SEO or consuming or saving server resources.

I would like to try to remove them and see what happens... But I find tons of guides on how to install them and none on how to remove them... so I have a few questions:

• is it possible to remove apcu and memcached?
• Most importantly is it possible to do it safely without destroying the server?
• and perhaps more importantly, is it such a stupid idea to remove them?

Additional information:

The server works fine, it has some spikes when a big cronjob starts (or when someone tries to attack it, but fail2ban takes care of it) but for the rest of the time it still has a lot of resources available. But slowly the memory fills up more and more, and everything is getting closer and closer to red, perhaps because of apcu or memcached?

FastCGI sent in stderr: "PHP message: PHP Fatal error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 137612647 bytes)

Already I increase 2 times in php.ini file. But again memory size exhausted happening. And also I got following error /app/source_code_shop/shop/sites/all/modules/contrib/memcache/dmemcache.inc on line 64" while reading response header from upstream.

We can't fixed this solution. Is it memcache error or memcache module error or php coding problem. Please give me proper solution how can solve php memory exhaust problem in drupal.

On my CentOS 7, Memcached is running and working on SSH but not working in the PHP file. I've followed this article: https://www.mynotepaper.com/install-memcached-on-centos-7. This method was working fine on my previous server.

I've tested Memcached using telnet. It works fine.

$ telnet 127.0.0.1 11211
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
set test 0 100 5
Hello
STORED
get test
VALUE test 0 5
Hello
END

After storing data using telnet, I've tested on SSH via PHP command. It works too:

php -r '$c = new Memcached(); $c->addServer("127.0.0.1", 11211); var_dump( $c->getAllKeys() );'
array(1) {
  [0]=>
  string(4) "test"
}

But in PHP file, it doesn't work. The PHP code:

<?php
$c = new Memcached();
$c->addServer("127.0.0.1", 11211);
var_dump( $c->getAllKeys() );
?>

It always shows bool(false). Here's my PHP info's screenshot.

Could you please tell me what's my mistake?

I already have memcached installed in my servers and I've modified the default php.ini to:

session.save_handler = memcached
session.save_path = "127.0.0.1:11211"

I'm using Amazon EC2 instances (Ubuntu 16.04 LTS) with Auto Scaling and Load Balancer, but I've a big question in my mind about the PHP memcached. First, explaining my problem: I've stored sessions in my Server A and I've another Server B also running. But, when I stop Server A (that I'm connected with sessions), the Load Balancer redirects me to Server B and it looks like the sessions are lost, because I'm disconnected of my website and he asks me to sign in again.

And I read this excerpt for use memcached for session storage on multiple servers (from here):

In your php.ini you should set session.save_path to the list of memcached servers, for example server1:11211, server2:11211.

But how can I say in who will be server1:11211 and server2:11211 being that I am using Auto Scaling and I may have "n" servers?

I had installed PHP 5.6.20 from this source. https://webtatic.com/packages/php56/

But I cannot install memcached. Just only memcache.
How to install memcached to PHP 5.6?

This is what i tried.

[root@testcentos ~]# yum -y install php56w-pecl-memcached.x86_64
Loaded plugins: fastestmirror
Setting up Install Process
Loading mirror speeds from cached hostfile
 * base: mirror2.totbb.net
 * epel: ftp.jaist.ac.jp
 * extras: mirrors.nwsuaf.edu.cn
 * remi-safe: mirror.neolabs.kz
 * updates: mirror2.totbb.net
 * webtatic: sp.repo.webtatic.com
Resolving Dependencies
--> Running transaction check
---> Package php56w-pecl-memcached.x86_64 0:2.2.0-2.w6 will be installed
--> Processing Dependency: php-pecl-igbinary(x86-64) for package: php56w-pecl-memcached-2.2.0-2.w6.x86_64
--> Processing Dependency: libmemcachedutil.so.2()(64bit) for package: php56w-pecl-memcached-2.2.0-2.w6.x86_64
--> Processing Dependency: libmemcached.so.11()(64bit) for package: php56w-pecl-memcached-2.2.0-2.w6.x86_64
--> Running transaction check
---> Package libmemcached10.x86_64 0:1.0.16-1.ius.el6 will be installed
---> Package php56w-pecl-igbinary.x86_64 0:1.2.1-2.w6 will be installed
--> Processing Conflict: libmemcached10-1.0.16-1.ius.el6.x86_64 conflicts libmemcached < 1.0
--> Finished Dependency Resolution
Error: libmemcached10 conflicts with libmemcached-0.31-1.1.el6.x86_64
 You could try using --skip-broken to work around the problem
 You could try running: rpm -Va --nofiles --nodigest