A.Thedefragfscommandshouldnotberunagainstfilesystemsandlogicalvolumesthatcontainmostlytransitoryinformation，suchas/tmp.
B.ThedefragfscommandshouldnotberunonalargeJFS2filesystemwhenrunningona32-bitkernel.
C.Thedefragfscommandcanimprovefilesystemperformancebyincreasingthefilesystem’scontiguousfreespace.
D.Thedefragfscommandcanonlyberunagainstfilesystemsthataremountedwithread-writepermissions.
正确答案：参考B
