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I'm running several Bind servers (v9.10.4) to provide DNS services to my users. Intermittently (about 30 seconds every 15 minutes) all recursive requests will fail and timeout. CPU and Memory on all the servers are in normal ranges and no errors are being logged on the servers. Does anyone have good tricks on tracking down Bind performance issues?

My problem is similar to the one described at BIND/DNSMASQ query hanging on ubuntu server 14.04.1 but the solution there didn't help me.

EDIT 2017-08-29:

Here's my redacted named.conf file if it's helpful. The slave.conf file that's included on the last line is just a file with a bunch of zone definitions in it.

acl "trusted" {
    ** redacted **
};

options {
        directory "/var/bind";
        pid-file "/run/named/named.pid";

        allow-query { trusted; };
        allow-query-cache { trusted; };
        allow-recursion { trusted; };
        allow-transfer { none; };
        allow-update { none; };

        dnssec-enable yes;
        dnssec-validation auto;
};

include "/etc/bind/rndc.key";
controls {
        inet 127.0.0.1 port 953 allow { 127.0.0.1/32; ::1/128; } keys { "rndc-key"; };
};

zone "." in {
        type hint;
        file "/var/bind/named.cache";
};

zone "localhost" IN {
        type master;
        file "pri/localhost.zone";
        notify no;
};

include "/etc/bind/slave.conf";
  • Have you managed to fix this? – Rui F Ribeiro Aug 25 '17 at 22:00
  • Not really. I discovered that having logging turned up too much (like you would have it when you're having problems) can cause problems for Bind. I turned logging off and tripled the number of servers handling those requests. It's better now but I don't think I really solved the ultimate issue. – David King Aug 28 '17 at 12:24
  • Hmmm odd. Have you raised the number of default clients? – Rui F Ribeiro Aug 28 '17 at 12:48
  • (i also have high logging, but that is an entirely different talk. BIND ought to be simple, had many servers and never had issues I could not solve) Are you sure it is not firewall or infra-structure limitations? – Rui F Ribeiro Aug 28 '17 at 18:24
  • I'm not entirely sure what you mean by the number of default clients. I can't find a client limit anywhere in the documentation. I've edited the question to include my named.conf if it's helpful. – David King Aug 29 '17 at 13:52

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