- Download Solr 6.2 and Zookeeper 3.4.6
- Launch Zookeeper $zkServer
- Launch two Solrs $bin\solr start -z localhost:2181 -e cloud
- stop Zookeeper
- get to new Admin UI. It's frozen. Respond with placeholders after few minutes. However, solr urls respond well.
- launch Zookeeper back, UI respond smoothly and rapidly.
I briefly checked chrome debug, I saw that every ...js response is slow, something like request filter might check zookeeper with timeout, but I don't know.