เจอปัญหา drupal มันชอบมี error ต่อไปหา memcache ไม่ได้
ลอง google ดูเจอ
http://www.couchbase.com/forums/thread/memcache-timeouts-app-logs
ลองดู messeges ของ memcache server ก็เจออะไรทำนองนี้
[27105943.508413] net_ratelimit: 133 callbacks suppressed
[27105943.508416] nf_conntrack: table full, dropping packet.
[27105943.519000] nf_conntrack: table full, dropping packet.
[27105943.534600] nf_conntrack: table full, dropping packet.
[27105943.534782] nf_conntrack: table full, dropping packet.
[27105943.540423] nf_conntrack: table full, dropping packet.
[27105943.542609] nf_conntrack: table full, dropping packet.
[27105943.548504] nf_conntrack: table full, dropping packet.
[27105943.554372] nf_conntrack: table full, dropping packet.
[27105943.569737] nf_conntrack: table full, dropping packet.
[27105943.573252] nf_conntrack: table full, dropping packet.
เลยลองแก้ตามเขา
เดิม
# sysctl net.ipv4.netfilter.ip_conntrack_max
net.ipv4.netfilter.ip_conntrack_max = 65565
# sysctl net.ipv4.tcp_max_tw_buckets
net.ipv4.tcp_max_tw_buckets = 262144
# sysctl net.ipv4.netfilter.ip_conntrack_tcp_timeout_established
net.ipv4.netfilter.ip_conntrack_tcp_timeout_established = 432000
# sysctl net.ipv4.tcp_window_scaling
net.ipv4.tcp_window_scaling = 1
เลยลองแก้ใน /etc/sysctl.conf
net.ipv4.tcp_max_tw_buckets = 1000000
net.ipv4.netfilter.ip_conntrack_max = 4194304
net.ipv4.netfilter.ip_conntrack_tcp_timeout_established = 120
net.ipv4.tcp_window_scaling = 1
ลองดูอาการอีกที
http://www.couchbase.com/forums/thread/memcache-timeouts-app-logs