单项选择题 WhenissuingtheCROSSCHECKcommandinRMAN，ifabackupfileCANNOTbefound，towhatstatusisthatfileset？（）

单项选择题 YourdatabaseissetinNOARCHIVELOGmodeandisbackedupeverynight.Thereare10redologgroupsonthedatabase，eachwiththreemembers，makingatotalof30redologfiles.Atlunchtimetheserverunexpectedlygetsshutdown.UponrestartingyounoticethatthedatafilebelongingtotheSYSTEMtablespacehasbecomecorrupted.Youalsonoticethattherehavebeen15logswitchesduringtheday.Whichsolutionshouldyouusetorecoverasmuchcommitteddataaspossible？（）

单项选择题 You have configured the following：  RMAN> CONFIGURE DEFAULT DEVICE TYPE TO ’sbt’； new RMAN configuration parameters：  CONFIGURE DEFAULT DEVICE TYPE TO ’sbt’； new RMAN configuration parameters are successfully stored RMAN> SHOW DEVICE TYPE； RMAN configuration parameters are： CONFIGURE DEVICE TYPE SBT PARALLELISM 1； # CONFIGURE DEVICE TYPE DISK PARALLELISM 1； #  RMAN> CONFIGURE DEVICE TYPE SET PARALLELISM 5；  RMAN> SHOW DEVICE TYPE； RMAN configuration parameters are： CONFIGURE DEVICE TYPE SBT PARALLELISM 5； CONFIGURE DEVICE TYPE DISK PARALLELISM 1； #  How many channels are allocated to SBT？（）