Hi All.
I am currently using memcache daemon in version 1.4.15 on one of my servers. The second one is executing php scripts which use mentioned memcache daemon (php53-pecl-memcache-2.2.5).
Memcache server: CentOS release 6.3 (Final) 2.6.32-279.5.2.el6.centos.plus.x86_64 uptime 184 days
PHP server: CentOS release 6.3 (Final) 2.6.32-279.19.1.el6.centos.plus.x86_64 uptime 43 days
The memcache server gets about: - 250Mb/s traffic - 4500 connections/s
On PHP server I get sometimes timeouts, ~20-30 daily. Both servers are not swapping, they have free memory, cpu is ~40% used max. But I have found some errors in netstat -s:
Memcache server: TCP 7251 failed connection attempts (incrementing) 56447 connection resets received (incrementing) TcpExt 36 packets pruned from receive queue because of socket buffer overrun (not incrementing) 2820 packets collapsed in receive queue due to low socket buffer (not incrementing) 459479 connections reset due to unexpected data (incrementing)
PHP server: TCP 540 failed connection attempts (incrementing) 381066 connection resets received (incrementing) TcpExt 7194 packets pruned from receive queue because of socket buffer overrun (incrementing) 250104 packets collapsed in receive queue due to low socket buffer (incrementing) 2447931 connections reset due to unexpected data (incrementing)
I have tuned tcp/ip a bit:
net.ipv4.tcp_fin_timeout = 5 net.ipv4.tcp_tw_reuse = 1 net.core.somaxconn = 1024 net.ipv4.tcp_max_syn_backlog = 4196 net.core.netdev_max_backlog = 4196 net.ipv4.tcp_sack = 0 net.ipv4.ip_local_port_range = 8192 65534
net.core.rmem_max = 8388608 net.core.wmem_max = 8388608 net.ipv4.tcp_rmem = 4096 65536 8388608 net.ipv4.tcp_wmem = 4096 65536 8388608
and set txqueuelen for interfaces (1Gb/s) to 5000.
but where to look next? May it be so that the php client version is buggy? Any other tips?
Best regards, Rafal.