Magento var/cache directory is empty

Question

A few day ago I try to install and configure Redis and Varnish (by Turpentine) for my Magento site v.1.8 .

After this, I decide to rollback and I get my old (working) local.xml (which has the configuration for APC and Memcached) and decide to disable the two modules (Cm_RedisSession, Nexcessnet_Turpentine) enditing their xml file in /app/etc/modules with the tag false.

From this point over the var/cache dir is empty.

I try to delete the var/ dir to check permission rights, and what happen is that the var folder is created immediatelly with an empty cache folder inside.

How can I check the Magento cache behavior? Maybe this is because the cache passes from APC or Memcached and exclude the var/cache dir (as I read here https://magento.stackexchange.com/a/11534/9166 ).

This is my cache configuration in local.xml

    ...
<cache>
    <backend>apc</backend>
    <slow_backend>database</slow_backend>
    <slow_backend_store_data>0</slow_backend_store_data>
    <auto_refresh_fast_cache>0</auto_refresh_fast_cache> 
    <prefix>nameofmysite_</prefix>
</cache>

<cache>
    <backend>memcached</backend>
    <slow_backend>database</slow_backend>
    <fast_backend>Memcached</fast_backend>
     <fast_backend_options>>
        <servers>
            <server>
                <host><![CDATA[127.0.0.1]]></host>
                <port><![CDATA[11211]]></port>
                <persistent><![CDATA[1]]></persistent>
            </server>
        </servers>
        <compression><![CDATA[0]]></compression>
        <cache_dir><![CDATA[]]></cache_dir>
        <hashed_directory_level><![CDATA[]]></hashed_directory_level>
        <hashed_directory_umask><![CDATA[]]></hashed_directory_umask>
        <file_name_prefix><![CDATA[]]></file_name_prefix>
    </fast_backend_options>

    <memcached>
        <servers>
            <server>
                <host><![CDATA[127.0.0.1]]></host>
                <port><![CDATA[11211]]></port>
                <persistent><![CDATA[1]]></persistent>
            </server>
        </servers>
        <compression><![CDATA[0]]></compression>
        <cache_dir><![CDATA[]]></cache_dir>
        <hashed_directory_level><![CDATA[]]></hashed_directory_level>
        <hashed_directory_umask><![CDATA[]]></hashed_directory_umask>
        <file_name_prefix><![CDATA[]]></file_name_prefix>
    </memcached>
</cache>
...

Obviously before this changes my var/cache/ dir was populated regularly.

Thanks.