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litespeed_wiki:nf_conntrack_table_full [2015/07/30 19:26] Michael Alegre removed |
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- | ===== How to fix “nf_conntrack: table full, dropping packet.” issue ===== | ||
- | during high traffic time, web site become much slower while low traffic is ok. a typical case is a download server, when there are many concurrent connections to download, many or all users feel much slower. one cause may be the linux conntrack table is full. | ||
- | ==== Check ==== | ||
- | #dmesg | tail | ||
- | nf_conntrack: table full, dropping packet. | ||
- | nf_conntrack: table full, dropping packet. | ||
- | nf_conntrack: table full, dropping packet. | ||
- | |||
- | if you see above, then the issue of conntrack table full is confirmed. | ||
- | |||
- | #sysctl -a | grep conntrack | ||
- | ... | ||
- | net.netfilter.nf_conntrack_max = 65536 | ||
- | net.netfilter.nf_conntrack_count = 68999 | ||
- | net.netfilter.nf_conntrack_buckets = 16384 | ||
- | ... | ||
- | | ||
- | #cat /sys/module/nf_conntrack/parameters/hashsize | ||
- | 16384 | ||
- | |||
- | if nf_conntrack_count is close to nf_conntrack_max or even larger, the problem will occur. | ||
- | |||
- | ==== Action ==== | ||
- | #sysctl -w net.netfilter.nf_conntrack_max=655360 | ||
- | net.netfilter.nf_conntrack_max = 655360 | ||
- | #echo 163840 > /sys/module/nf_conntrack/parameters/hashsize | ||
- | |||
- | ==== Permanent Change ==== | ||
- | edit /etc/sysctl.conf, add following line: | ||
- | net.netfilter.nf_conntrack_max=655360 | ||
- | edit /etc/rc.local, add following line: | ||
- | echo 163840 > /sys/module/nf_conntrack/parameters/hashsize |