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<span>We have a resolver on Ubuntu 18.04, using the Ubuntu-packaged bind9 (1:9.11.3+dfsg-1ubuntu1.11).<br>
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<div>The server seems to leak memory, and bind9 needs restarting every couple of weeks.<br>
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<div>If we ignore it then the linux OOM-killer steps up and "handles" the problem for us.<br>
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<div><br>
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<div>We have enabled bind stats like so in /etc/bind/named.conf.options:<br>
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<div><br>
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<div>statistics-channels {<br>
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<div> inet 127.0.0.1 port 8653 allow { 127.0.0.1; };<br>
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<div>};<br>
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<div><br>
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<div>and have been collecting stats into a zabbix server with the scripts from<br>
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<div>https://github.com/Pesticles/Zabbix-Bind9-Statistics-Collection.<br>
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<div><br>
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<div>I can emit arbitrary stats on demand like so:<br>
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<div><br>
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<div># wget http://localhost:8653 -qO - | xmllint --format - | grep -E 'TreeMemTotal|TotalUse'<br>
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<div> <counter name="TreeMemTotal">234006180</counter><br>
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<div> <counter name="TreeMemTotal">287792</counter><br>
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<div> <TotalUse>16510250005</TotalUse><br>
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<div><br>
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<div>For example, just today, TotalUse has increased from about 4GB at 07:00 to about 15GB at 16:00.<br>
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<div>Also today, TreeMemTotal has increased from about 70MB at 07:00 to about 220MB at 16:00.<br>
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<div><br>
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<div>There are 2 things that I would like more insight into:<br>
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<div><br>
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<div>(1) why is TreeMemTotal (cache tree memory total) constantly increasing?<br>
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<div> We restart bind9 when it gets over 1GB. This memory use is not reflected<br>
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<div> in the actual memory use on the machine, as reported by top/free.<br>
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<div><br>
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<div>(2) what is TotalUse measuring? I assumed bytes, but this measure gets<br>
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<div> over 100GB on a machine with only 2GB RAM, and 10G disk on /var<br>
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<div> (only 2.3G used), so I wonder if it is measuring something else.<br>
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<div> It is in the /statistics/memory/summary/ section of the XML emitted<br>
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<div> on port 8653, so it certainly looks like memory bytes e.g.<br>
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<div>...<br>
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<div> <summary><br>
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<div> <TotalUse>16969284048</TotalUse><br>
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<div> <InUse>170518137</InUse><br>
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<div> <BlockSize>203685888</BlockSize><br>
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<div> <ContextSize>7959160</ContextSize><br>
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<div> <Lost>0</Lost><br>
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<div> </summary><br>
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<div> </memory><br>
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<div></statistics><br>
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<div><br>
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<div><br>
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<div>Thanks,<br>
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<div>Alistair<br>
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<span></span><br>
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