单项选择题
A.sar
B.topas
C.iostat
D.vmstat
单项选择题 Asystemadministratorreceivedthefollowingmessagewhiletryingtosshtoaserver：connectiontimedout.Theadministratorpingedtheserverandhadnoresponse.Theadministratorthenpingedthegateway，andwassuccessful.Whichtoolcouldtheadministratorusenexttoisolatetheproblem？（）
单项选择题 AusercallstoreporttheyaregettingI/Oerrorsonafilesystem.Whichofthefollowingtoolsshouldbeusedtoisolatethisproblem？（）
单项选择题 Aremoteuseristryingtotelnettotheproductionserver.Thesessionisgettingatimeouterror.Whichcommandshouldtheuserissuetoverifythenetworkconnection？（）