Drush fails "unable to copy" to drush-backups? When I run $ drush pm-update I receive an "Unable to copy" error. 


  Unable to copy /mnt/hd0/vhosts/yourwebsite.com/drupal-7.36 to /home/ec2-user/drush-backups/opencall/20150422140414/drupal.               [error]
  Unable to move /mnt/hd0/vhosts/yourwebsite.com/drupal-7.36 to /home/ec2-user/drush-backups/opencall/20150422140414/drupal.               [error]
  Failed to backup project directory /mnt/hd0/vhosts/yourwebsite.com/drupal-7.36 to 


Any thoughts? I'm sure it will run if I use sudo but that has other undesirable consequences.
Think I've solved it. 

Looks like someone previously ran Drush in the sudo environment and that had the effect of setting permissions to 6226 all over the place. 

Updated manually and fixed permissions as I went.