Heavy IO causes session loss

[dfredell]

When a Triton host is under heavy load the mysql-primary is unable to read the consul session file /tmp/mysql-session which then causes the mysql-primary to fail and loose its consul healthy service.
The session is read at

mysql/bin/manager/discovery.py

Line 72 in 464f2b9

session_id = f.read()

The work around is when this happens to delete the /tmp/mysql-session, and sometimes then run python /usr/local/bin/manage.py run_as_primary

[dfredell]

This might have been solved by setting the ZFS Priority to the same value on all of my Triton Packages. I have mostly migrated off of the autopilotpattern/mysql so IDK if that would fix it. It solved other problems though.