BIND response time is relatively high

hi ,



I noticed that at peak hours, BIND response time is relatively high for some servers.
BIND 9.9.5-P1
non-cached query takes over 700ms

I set some kernel parameters to tune the network and sockets for redhat 6 and set some global options to tune the BIND by modifying the cache settings, but neither I get the cache I set the limit to filed up, nor I get better performance.



some settings are as below,



kernel sysctl:

============

net.ipv4.ip_local_port_range = 1024 65535
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.core.rmem_max = 33554432
net.core.wmem_max = 33554432

net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.tcp_max_orphans = 400000

net.core.somaxconn = 4096

net.ipv4.tcp_rmem = 4096 87380 33554432
net.ipv4.tcp_wmem = 4096 65536 33554432





bind named.conf global options:

=========================

cleaning-interval 1440;
max-cache-ttl 2419200;
max-ncache-ttl 86400;
max-cache-size 5120m;



server specs:

===========

memory is 8GB


memory usage is not exceeding 20% or 1.7GB while the cache is limited to 5GB as shown in the settings above, i wouldn't be more happier if i could have seen memory utilization spikes to the sky.



could you please suggest !!!







thanks