Which of the following commands should be used to view and change the network filesystem tuning parameters available on the system？（）

单项选择题Whichofthefollowingcommandsdisplaysthenumberofsystemcallspersecondthatarebeingexecuted？（）

A. sar
B. pstat
C. iostat
D. filemon

单项选择题Whichofthefollowingcommandsshouldbeusedtoshowhowmuchdataisreadfromorwrittentoaparticularlogicalvolume，giventhereareseveralotherlogicalvolumesonthesamedisk？（）

A. sar
B. lslv
C. iostat
D. filemon

单项选择题WhichofthefollowingcommandsshouldbeusedtomonitordiskutilizationduringthetimeasystemisexperiencingadiskI Operformanceproblem？（）

A. istat
B. topas
C. vmstat
D. filemon

单项选择题Afterrunningthevmstatcommand，whichofthefollowingwouldmostlikelycausethevalueintheblockedcolumntobeunusuallyhigh？（）

A. Kernel thread
B. Too many users
C. Memory shortage
D. Network contention

单项选择题Whichofthefollowingcommandsismostusefulininitiallycollectingdatatodetermineanetworkperformanceproblem？（）

A. ping
B. trace
C. ifconfig
D. lsattr