Menu
First, when memcached gets full, it will start removing items from the cache using the Least Recently Used algorithm. Second, you can have multiple instances of memcached running, adding them gets complicated because it will change the hashing algorithm used to determine which cache the data is in.
Even though exposure of the memcached service has been known to be a security risk for some time, widespread exploitation to perform DDoS attacks utilizing techniques that result in very large amplification of attack traffic was not previously known to be common.
With Memcached you can build highly scalable distributed caching solutions designed to provide fast and consistent performance.
Memcached is a distributed caching system, whereas APC is non-distributed - and mainly an opcode cache.
If (and only if) you have a web application which has to live on different webservers (loadbalancing), you have to use memcache for distributed caching. If not, just stick to APC and its cache.
You should always use an opcode cache, which APC is (also APC will get integrated into php6 iirc, so why not start using it now).
You can/should use both for different purposes.
Memcached if you need to preserve state across several web servers (if you're load balanced and it's important that what's in the cache is the same for all servers).
APC if you just need access to quick memory to read (& write) on a (or each) server.
Remember APC can also compile and speed up your script execution time. So you could for example be using APC for increased execution performance, while using memcached for cache storage.
The main advatage of APC is opcode cache. Since PHP 5.5 integrated OpCache to its core and APC for PHP 5.4 is still flagged as beta, it's not official annoucement, but the development of APC would be dropped in near future.
So I would recommend you to choose Memcached.
I use both one for speed and the other to sync all my servers. If you do use memcache then please do keep in mind of the open ports which you will need to block with iptables.
Hey Thomaschaaf, I hope this is not tool late for you but please note that APC has some issues related to "user-cache". To make a long story short, when you set time-outs for cache entries, or if your apache crashes inside internal APC code (timeout, for example), then you may suffer some problems.
I have an entry about the issue here: http://nirlevy.blogspot.com/2009/06/apc-futexwait-lockdown-make-your-apache.html, and you should also read http://t3.dotgnu.info/blog/php/user-cache-timebomb.html (from one of the APC developers i think)
I use only APC since APC is a code cache and acts like memcache ! Only 1 config file instead of 2.
And only 1 place to monitor both cache.....
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With