I'm running squid 3.4.5-20140514-r13135 I started switching over to diskd from aufs because I was tired of all the is_empty() crashes. I stopped squid, removed the cache directory and swapfile completely, then started squid with the '-z' option to rebuild the cache directory. Within a half-hour my cache.log file started reporting lines like: 2014/05/21 11:09:26 kid1| WARNING: swapfile header inconsistent with available data 2014/05/21 11:09:56 kid1| WARNING: swapfile header inconsistent with available data 2014/05/21 11:10:49 kid1| WARNING: swapfile header inconsistent with available data 2014/05/21 11:11:04 kid1| WARNING: swapfile header inconsistent with available data 2014/05/21 11:11:19 kid1| WARNING: swapfile header inconsistent with available data 2014/05/21 11:11:34 kid1| WARNING: swapfile header inconsistent with available data 2014/05/21 11:12:04 kid1| WARNING: swapfile header inconsistent with available data At least it is not crashing. This instance was started with a clean cache. Mike Mitchell