单项选择题 Company.com with a newly installed cluster has been checking the logfiles to determine if the  cluster has had any recent activity. The non-IP RS232 heartbeat connection seems to be having a difficulty. The serial network goes down，and then a couple of minutes later comes back up again. This pattern is repeated many times in the log.  If this system was installed without regard to best practices， what is the most likely problem with the serial network？（）

单项选择题 Duringaclusterfunctionalitytest，andadministratorperformsagracefulstopforNode’B’inathree-nodecluster.WhatistheexpectedstateoftheclusterafterNode’B’successfullycompletes？（）

单项选择题 During the process of fallover testing， a client/server database needs to be tested. On the AIX Server， start/stop/cleanup scripts and server application functionality have been tested.  Before moving onto the next step of fallover testing，what action must be completed？（）