As suggested in this post, Gerrit 2.13.6 takes ages to start, it is probably due to missing entropy for the RNG. You can have a try to install haveged How to Setup Additional Entropy for Cloud Servers Using Haveged.
for centos
yum install haveged
chkconfig haveged on
service haveged start
gerrit.sh restart
这样重启gerrit就很快启动了,之前少则15分钟多则半小时。