Am 22.03.2013 um 15:37 schrieb Rafał Radecki <radecki.rafal at gmail.com>: > 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? just supposing - are you using httpd? -> listenbacklog -- LF