Configuring Memcache + CakePHP, "Cache not configured properly" error

I'm setting up cacheing for a CakePHP application and having a really hard time getting it to talk to Memcache.

I've written the caching code while testing against the File based caching engine, and all the logic is solid. When I watch debug traffic, caches hit, miss, and expire properly. I wanted to switch over to Memcache because the Filesytem based cache doesn开发者_如何学JAVA't really offer any performance improvement, but I can't seem to get it to work at all.

As soon as I change the Caching engine in Cache::config to Memcache, I get the following error:

Warning (512): Cache not configured properly. Please check Cache::config(); in APP/config/core.php [CORE/cake/libs/configure.php, line 663]

This happens with a simple configuration call, like:

Cache::config('default', array(
    'engine' => 'Memcache'
    ));

Or a more complicated one, like the default one suggested in core.php:

Cache::config('default', array(
        'engine' => 'Memcache', //[required]
        'duration'=> 3600, //[optional]
        'probability'=> 100, //[optional]
        'prefix' => Inflector::slug(APP_DIR) . '_', //[optional]  prefix every cache file with this string
        'servers' => array(
        '127.0.0.1:11211' // localhost, default port 11211
        ), //[optional]
        'compress' => false, // [optional] compress data in Memcache (slower, but uses less memory)
        ));

Cache.check is set to true, eg Configure::write('Cache.check', true); and Cache.disable is not set. Again, all the caching logic works great as long as I'm using 'engine' => 'File'.

I get the same error whether memcached is running or not. This error seems to encompass a ton of different problems - extensive searching has revealed a huge variety of potential solutions to problems with this error message. I've double checked that my tmp directories exist (per http://ryan.ifupdown.com/2009/08/05/warning-512-cache-not-configured-properly-please-check-cacheconfig-in-appconfigcore-php-corecakelibsconfigure-php-line-663/), I'm running on Ubuntu, so there are no pathing issues (which have been a problem in the past, per https://trac.cakephp.org/ticket/4433 and http://cakephp.1045679.n5.nabble.com/cake-1-2-problem-with-cache-td1302563.html). I am running a relatively old version of Cake (1.2.5), but I tried upgrading and had the same error message (along with a million other upgrade-related errors that I don't really have time to hunt down.)

Is there any way to get more detailed information out of Cake about what's actually going wrong? I get the feeling that this error is just a catch-all error for anything that goes wrong in the cache class initialization, and there are tons of potential problems. Changing the debug level up to 3 doesn't reveal anything more. If I could get more info I might be able to do something, but I'm totally flying blind. I'm a mostly-novice Cake user, so any general guidance about best practices for dealing with bizarre Cake bugs would be much appreciated!

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You need to install the Memcache lib for PHP. You should be able to install it using the "php5-memcache" package.

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On Ubuntu 10.04, I had to install both memcached AND memcache in order to get it to work.

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Usually this means that the memcache server isn't actually running. Can you make sure that the server is running locally, and on port 11211 (which is the default)?

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You have to make sure the memcache (not "memcached") is 1) installed and 2) running. 1) Check if extension=memcache.so is present in php.ini 2) Follow this instructions to start automatically memcache