If ZK loses quorum, Solr goes read-only. That's how it's designed to work. I don't know of any workaround for that.
That makes sense. CPU spiking in solr is because solr's index calls are holding threads because zookeeper is down as per solr? -- Sent from: https://lucene.472066.n3.nabble.com/Solr-User-f472068.html