title: PHP Fatal error when deploying Symfony2 project using Capifony
body: <p>When deploying my Symfony2 project to my server I occassionally get the following error:</p>
  
  <pre><code>PHP Fatal error:  Uncaught exception 'ErrorException' with message 'proc_open(): 
  fork failed - Cannot allocate memory' in 
  in phar:///var/www/xyz.co.uk/releases/20130320161122/composer.phar/vendor/
  symfony/console/Symfony/Component/Console/Application.php:982
  </code></pre>
  
  <p><strong>Update</strong></p>
  
  <p>Full error message is below which occurs after <code>--&gt; Updating Composer dependencies</code>:</p>
  
  <pre><code>*** [err :: x.xx.xx.xxx] PHP Fatal error:  Uncaught exception 'ErrorException' with message 'proc_open(): fork failed - Cannot allocate memory' in phar:///var/www/xyz.co.uk/releases/20130320161815/composer.phar/vendor/symfony/console/Symfony/Component/Console/Application.php:982
  *** [err :: x.xx.xx.xxx] Stack trace:
  *** [err :: x.xx.xx.xxx] #0 [internal function]: Composer\Util\ErrorHandler::handle(2, 'proc_open(): fo...', 'phar:///var/www...', 982, Array)
  *** [err :: x.xx.xx.xxx] #1 phar:///var/www/xyz.co.uk/releases/20130320161815/composer.phar/vendor/symfony/console/Symfony/Component/Console/Application.php(982): proc_open('stty -a | grep ...', Array, NULL, NULL, NULL, Array)
  *** [err :: x.xx.xx.xxx] #2 phar:///var/www/xyz.co.uk/releases/20130320161815/composer.phar/vendor/symfony/console/Symfony/Component/Console/Application.php(900): Symfony\Component\Console\Application-&gt;getSttyColumns()
  *** [err :: x.xx.xx.xxx] #3 phar:///var/www/xyz.co.uk/releases/20130320161815/composer.phar/vendor/symfony/console/Symfony/Component/Console/Application.php(865): Symfony\Component\Console\ in phar:///var/www/xyz.co.uk/releases/20130320161815/composer.phar/vendor/symfony/console/Symfony/Component/Console/Application.php on line 982
  *** [deploy:update_code] rolling back
  failed: "sh -c 'sh -c '\\''cd /var/www/xyz.co.uk/releases/20130320161815 &amp;&amp; php composer.phar update --no-scripts --verbose --prefer-dist'\\'''" on x.xx.xx.xxx
  </code></pre>
  
  <p>This doesn't happen ALL the time but just sometimes. I've allocated 256M in my apache and cli php.ini file on the server but still sometimes receive the error.</p>
  
  <p>How much memory does Symfony require? Do I need to increase it further? I thought this would be enough. </p>