title: mysqldump: Can't create/write to file error from amazon RDS
body: <p>I am attempting to dump a database running on Amazon's RDS service, mysql version 5.5.27. Here's the command I'm running:</p>
  
  <pre><code>my-ec2-instance# mysqldump -hec2-xx-xx-xx-xx.compute-1.amazonaws.com -uuser -pwhatever mydb
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>mysqldump: Couldn't execute 'show fields from `MyTable`': Can't create/write to file '/tmp/#sql_1405_0.MYI' (Errcode: 2) (1)
  </code></pre>
  
  <p>So, since the error message says its failing on "show fields", I tried to execute "Show fields from MyTable" from the mysql interpreter directly. I get what appears to be a file issue:</p>
  
  <pre><code>mysql&gt; show fields from MyTable;
  ERROR 1 (HY000): Can't create/write to file '/tmp/#sql_1405_0.MYI' (Errcode: 2)
  </code></pre>
  
  <p>however, on the same EC2 instance that I am getting this error on, I can create this file and delete it:</p>
  
  <pre><code>my-ec2-instance# touch /tmp/#sql_1405_0.MYI; ls /tmp/#sql*;rm /tmp/#sql_1405_0.MYI
  /tmp/#sql_1405_0.MYI
  rm: remove regular empty file `/tmp/#sql_1405_0.MYI'?
  </code></pre>
  
  <p>I've tried the same thing from my local machine, and I get the same result. Googling this has not borne fruit. How can I prevent this error from occurring?</p>