ping 返回 no buffer space available 解决方法

1. 云主机当前常规并发比较大,  约有 1900 个常规连接

[root@chao-data07 ~]# netstat -nt | grep EST | wc -l
1867

2. 当前出现 arp 表不正常现象

见到下面错误信息

Mar 24 14:06:31 chao-data07 dhclient[1112]: DHCPREQUEST on eth0 to 10.199.212.200 port 67 (xid=0xd488179)
Mar 24 14:06:31 chao-data07 dhclient[1112]: send_packet: No buffer space available
Mar 24 14:06:31 chao-data07 kernel: Neighbour table overflow.
Mar 24 14:06:40 chao-data07 dhclient[1112]: DHCPREQUEST on eth0 to 10.199.212.200 port 67 (xid=0xd488179)
Mar 24 14:06:40 chao-data07 dhclient[1112]: DHCPACK from 10.199.212.200 (xid=0xd488179)
Mar 24 14:06:41 chao-data07 dhclient[1112]: bound to 10.199.196.108 -- renewal in 34441 seconds.
Mar 24 14:07:13 chao-data07 kernel: Neighbour table overflow.
Mar 24 14:07:13 chao-data07 kernel: Neighbour table overflow.
Mar 24 14:07:14 chao-data07 kernel: Neighbour table overflow.
Mar 24 14:07:14 chao-data07 kernel: Neighbour table overflow.
Mar 24 14:07:16 chao-data07 kernel: Neighbour table overflow.
Mar 24 14:07:16 chao-data07 kernel: Neighbour table overflow.

Mar 24 23:40:42 chao-data07 dhclient[1112]: DHCPREQUEST on eth0 to 10.199.212.200 port 67 (xid=0xd488179)
Mar 24 23:40:42 chao-data07 dhclient[1112]: send_packet: No buffer space available

Mar 25 10:18:08 chao-data07 kernel: __ratelimit: 24 callbacks suppressed
Mar 25 10:18:08 chao-data07 kernel: Neighbour table overflow.
Mar 25 10:18:08 chao-data07 kernel: Neighbour table overflow.

ping 时候返回  no buffer space available 信息

解决方法:

echo 4096 > /proc/sys/net/ipv4/neigh/default/gc_thresh1
echo 8192 > /proc/sys/net/ipv4/neigh/default/gc_thresh2
echo 20480 > /proc/sys/net/ipv4/neigh/default/gc_thresh3

暂时解决问题.