单项选择题 An administrator is ordering a new Power 550. They will mirror rootvg and are concerned about single points of failure. Which of the following features should be ordered？（）

单项选择题 Following a system boot，the display indicates that previously detected hardware is missing.  Which of the following commands would identify the missing hardware？（）

单项选择题 An administrator has a two-disk volume group （testvg） with one logical volume （testlv） which has just been mirrored across both disk drives. Which of the following commands can be used to turn off quorum？（）