title: Error trying to start Notification Server
body: <p>I was trying to start Phabricator's <em>Notification Server</em>, but experienced the following error:</p>
  
  <pre><code>/phabricator/phabricator/bin/aphlict start
  
  [2015-11-16 18:41:08] EXCEPTION: (FilesystemException) Requested path '/var/tmp/aphlict/pid' is not writable. at [&lt;phutil&gt;/src/filesystem/Filesystem.php:1081]
  arcanist(head=master, ref.master=9dd6eafb5254), phabricator(head=master, ref.master=50d158a8c4d9), phutil(head=master, ref.master=e9ed72483a14)
    #0 Filesystem::assertWritable(string) called at [&lt;phutil&gt;/src/filesystem/Filesystem.php:73]
    #1 Filesystem::assertWritableFile(string) called at [&lt;phutil&gt;/src/filesystem/Filesystem.php:89]
    #2 Filesystem::writeFile(string, string) called at [&lt;phabricator&gt;/src/applications/aphlict/management/PhabricatorAphlictManagementWorkflow.php:140]
    #3 PhabricatorAphlictManagementWorkflow::willLaunch() called at [&lt;phabricator&gt;/src/applications/aphlict/management/PhabricatorAphlictManagementWorkflow.php:249]
    #4 PhabricatorAphlictManagementWorkflow::executeStartCommand() called at [&lt;phabricator&gt;/src/applications/aphlict/management/PhabricatorAphlictManagementStartWorkflow.php:15]
    #5 PhabricatorAphlictManagementStartWorkflow::execute(PhutilArgumentParser) called at [&lt;phutil&gt;/src/parser/argument/PhutilArgumentParser.php:406]
    #6 PhutilArgumentParser::parseWorkflowsFull(array) called at [&lt;phutil&gt;/src/parser/argument/PhutilArgumentParser.php:301]
    #7 PhutilArgumentParser::parseWorkflows(array) called at [&lt;phabricator&gt;/support/aphlict/server/aphlict_launcher.php:23]
  </code></pre>
  
  <p>The directory in question seems to be writable:</p>
  
  <pre><code>ls -l /var/tmp/aphlict
  
  total 4
  drwxr-xr-x 2 root root 4096 Nov 16 13:40 pid
  </code></pre>
  
  <p>If it matters, I'm running all operations as non-'root' on Ubuntu 14.04 LTS system.</p>