<p>I am writing this question to share the solution we found in our company.
We migrated Solr over a docker only solution to a kubernetes solution.</p>
<p>On kubernetes the environment ended up with slowness.
At least for me the solution was atypical.</p>
<p><strong>Environment:</strong></p>
<ul>
<li>solr(8.2.0) with just one node</li>
<li>solr database with 250GB on disk</li>
<li>kubernetes over Rancher</li>
<li>Node with 24vcpus and 32GB of Ram</li>
<li>Node hosts Solr and nginx ingress</li>
<li>Reserved 30GB for the Solr pod in kubernetes</li>
<li>Reserved 25GB for the Solr</li>
</ul>
<p><strong>Expected Load:</strong></p>
<ul>
<li>350 updates/min (pdf documents and html documents)</li>
<li>50 selects/min</li>
</ul>
<p>The result was Solr degrading over time having high loads on host. The culpirit was heavy disk access.</p>

<p>After one week of frustrated adjustments this is the simple solution we found:</p>
<p>Solr JVM had 25 GB. We decreased the value to 10GB.</p>
<p>This is the command to start solr with the new values:</p>
<p>/opt/solr/bin/solr start -f -force -a '-Xms10g -Xmx10g' -p 8983</p>
<p>If someone can explain what happened that would be great.
My guess is that solr was trying to make cash and kubernetes was reapping this cache. So Solr ended up in a continuous reading of the disk trying to build its cache.</p>
