We are fine tuning sysctl network stack on Linux OS and  change keepalive intervals for much better “response” times and load. These settings are lowered on our all managed performance servers that do host large sites – Drupal, Wordpress and custom LAMP services.

Enter the following lines in /etc/sysctl.conf

net.ipv4.tcp_keepalive_probes = 2
net.ipv4.tcp_keepalive_intvl = 30

And execute “sysctl -p” to set these settings in real-time.

By default it’s for Linux (Fedora, Redhat, Centos):

net.ipv4.tcp_keepalive_probes=9
net.ipv4.tcp_keepalive_intvl = 75

Enjoy!

We performed Bind 9.4.2 benchmarking using our Gigabit network and Linux server nodes. The following performance was easily recorded using one zone and doing IN A requests using queryperf tool.

DNS Query Performance Testing Tool
Version: $Id: queryperf.c,v 1.8.192.4 2007/09/05 07:44:57 marka Exp $

[Status] Processing input data
[Status] Sending queries (beginning with 192.168.3.20)
[Status] Testing complete

Statistics:

Parse input file:     once
Ended due to:         reaching end of file

Queries sent:         514229 queries
Queries completed:    514229 queries
Queries lost:         0 queries
Queries delayed(?):   0 queries

RTT max:              0.000861 sec
RTT min:              0.000172 sec
RTT average:          0.000678 sec
RTT std deviation:    0.000028 sec
RTT out of range:     0 queries

Percentage completed: 100.00%
Percentage lost:        0.00%

Started at:           Tue Feb  5 06:32:42 2008
Finished at:          Tue Feb  5 06:33:00 2008
Ran for:              17.732512 seconds

Queries per second:   28999.219062 qps

When configured with forwarded option – this is when master forwards to a back-end BIND server and then replies back to the client. The following performance was recorded:
DNS Query Performance Testing Tool
Version: $Id: queryperf.c,v 1.8.192.4 2007/09/05 07:44:57 marka Exp $

[Status] Processing input data
[Status] Sending queries (beginning with 192.168.3.10)
[Timeout] Query timed out: msg id 1
[Timeout] Query timed out: msg id 2
[Timeout] Query timed out: msg id 3
[Timeout] Query timed out: msg id 4
[Timeout] Query timed out: msg id 5
[Timeout] Query timed out: msg id 6
[Timeout] Query timed out: msg id 7
[Timeout] Query timed out: msg id 8
[Timeout] Query timed out: msg id 9
[Timeout] Query timed out: msg id 10
[Timeout] Query timed out: msg id 11
[Timeout] Query timed out: msg id 12
[Timeout] Query timed out: msg id 13
[Timeout] Query timed out: msg id 14
[Timeout] Query timed out: msg id 15
[Timeout] Query timed out: msg id 16
[Timeout] Query timed out: msg id 17
[Status] Testing complete

Statistics:

Parse input file:     once
Ended due to:         reaching end of file

Queries sent:         500000 queries
Queries completed:    499983 queries
Queries lost:         17 queries
Queries delayed(?):   0 queries

RTT max:              0.009379 sec
RTT min:              0.000369 sec
RTT average:          0.003022 sec
RTT std deviation:    0.000701 sec
RTT out of range:     0 queries

Percentage completed: 100.00%
Percentage lost:        0.00%

Started at:           Tue Feb  5 06:26:58 2008
Finished at:          Tue Feb  5 06:28:19 2008
Ran for:              80.786053 seconds

Queries per second:   6188.976704 qps

The performance as a standard Bind master server was almost 5 times faster than using 3 node forwarder set-up where one server node was a benchmark traffic generator.