I built a new system with squid 3.1.20 a few weeks ago and my cache.log reports an assertion failed: membuf.cc:280: "size < capacity" error and squid restarts about once a day. My server is SLES 11 SP2, 64bit, 12GB RAM. I'm also running squidclamav 6.8 , icap 0.2.1, and ClamAV 0.97.5. My squid.conf file is below. My original server was squid 3.1.16 on SLES 11 SP1 which was running for 6-8 months without any problems. Any help is appreciated. # # Recommended minimum configuration: # acl manager proto cache_object acl localhost src 127.0.0.1/32 ::1 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1 # Example rule allowing access from your local networks. # Adapt to list your (internal) IP networks from where browsing # should be allowed acl localnet src 10.10.0.0/16 # RFC1918 possible internal network acl localnet src fc00::/7 # RFC 4193 local private network range acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines acl SSL_ports port 443 acl SSL_ports port 7001 acl SSL_ports port 8004 acl Safe_ports port 80 # http acl Safe_ports port 81 # http acl Safe_ports port 21 # ftp acl Safe_ports port 443 # https acl Safe_ports port 70 # gopher acl Safe_ports port 210 # wais acl Safe_ports port 1025-65535 # unregistered ports acl Safe_ports port 280 # http-mgmt acl Safe_ports port 488 # gss-http acl Safe_ports port 591 # filemaker acl Safe_ports port 777 # multiling http acl CONNECT method CONNECT acl snmppublic snmp_community cadc acl snmpsrv src 10.10.2.140 snmp_access allow snmppublic snmpsrv snmp_incoming_address 10.10.2.225 snmp_port 3401 # Recommended minimum Access Permission configuration: # Only allow cachemgr access from localhost acl cachemgr src 10.10.2.142 http_access allow manager cachemgr http_access deny manager # Deny requests to certain unsafe ports http_access deny !Safe_ports # Deny CONNECT to other than secure SSL ports http_access deny CONNECT !SSL_ports # We strongly recommend the following be uncommented to protect innocent # web applications running on the proxy server who think the only # one who can access services on "localhost" is a local user #http_access deny to_localhost # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS acl libsyn dstdomain .libsyn.com http_access deny libsyn # Example rule allowing access from your local networks. http_access allow localnet http_access allow localhost # And finally deny all other access to this proxy http_access deny all # Squid normally listens to port 3128 http_port 10.10.2.225:3128 # We recommend you to use at least the following line. hierarchy_stoplist cgi-bin ? # Uncomment and adjust the following to add a disk cache directory. cache_replacement_policy heap LFUDA cache_dir aufs /cache/cache 16384 16 256 # Leave coredumps in the first cache dir coredump_dir /var/log/squid # Add any of your own refresh_pattern entries above these. refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0 refresh_pattern . 0 20% 4320 icap_enable on icap_send_client_ip on icap_send_client_username on icap_client_username_encode off icap_client_username_header X-Authenticated-User icap_preview_enable on icap_preview_size 1024 icap_service service_req reqmod_precache bypass=1 icap://127.0.0.1:1344/squidclamav adaptation_access service_req allow all icap_service service_resp respmod_precache bypass=1 icap://127.0.0.1:1344/squidclamav adaptation_access service_resp allow all access_log /var/log/squid/access.log logfile_rotate 5 cache_mgr squid@xxxxxxxxxxxxxxx ftp_user squid@xxxxxxxxxxxxxxx dns_nameservers 156.132.106.29 refresh_all_ims on shutdown_lifetime 5 seconds max_filedescriptors 4096 cache_effective_user squid ipcache_size 4096 cache_mem 512 MB memory_replacement_policy lru maximum_object_size 10240 KB