We are caching large files only when it reach to around between 2TB and 2.5TB(cant be sure bec. Its from graph) store_swap_size became negative. I thought swap file is corrupt so its been deleted and rebuild. But still the same. squid-2.HEAD-20110824 Uname -a Linux localhost 2.6.32-24-server #39-Ubuntu SMP Wed Jul 28 06:21:40 UTC 2010 x86_64 GNU/Linux (Ubuntu server) -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.