http://docs.elgg.org/wiki/Installation/Requirements

ok..

We will be releasing cassandra integration next year.  Stay tuned.

Shruti: Can you place any other php page on /var/www/MYDIR and see whether it is visible or not?

If mod_rewrite is enabled and it doesn't work you might try two additional things:

• Set "AllowOverride All" either for the Elgg installation directory or in for the installation in general. This option can be defined for example in Apache's http.conf or in default-server.conf. The option would look like

<Directory "path_to_elgg_root_directory">

AllowOverride All

</Directory>

• In Elgg's .htaccess file in the Elgg root directory set the variable RewriteBase according to your installation. For example if your domain is http://localhost/MyWebCom.com/ it would be

RewriteBase /MyWebCom.com/

If you have placed the source code in /var/www/elgg-1.8.0.1, the url for your site should be http://localhost/elgg-1.8.0.1/ unless you have edited your apache configuration. I'm surprised it installed like that.