HBase uses ~40MB, and with Phoenix we use ~56MB of Perm space out of 64MB by default. Every Filter and Coprocessor increases that.
Running out of perm space triggers a stop the world full GC of the entire heap. We have seen this in misconfigured cluster.
Should we default to -XX:PermSize=128m -XX:MaxPermSize=128m out of the box as a convenience for users?