单项选择题 An administrator attempted to run a sar -u report and received the following error：   sar： 0551-201 Cannot open /var/adm/sa/sa07.   Which of the following should be scheduled in adm’s crontab to obtain sar reports？（）

单项选择题 A system administrator periodically receives calls from users who complain about poor performance with their application. Use the following sar command output to answer the question： Which of the following system resources need more investigation？（）

单项选择题 A system administrator ran the vmstat command because of performance problems. The output of the vmstat is given： Based on the output， which of the following is insufficient？（）