DBA Interview Questions

1) Primary database scn is 22 and standby SCN is 24 how you will resolve this issue.

 2) Archive log got deleted before shipped to standby location how you will resolve this issue.

 3) 3 users running same select but one of them response time is 1hr and for other few minutes how u will diagnose this.

 4) What is advantage of ASM over os storage and raw storage.

 5) What is remastering in RAC

 6) How you can see database version at OS level.

 7) A job is running since long it was working fine earlier how you will check that How you will suggest joins to developer

 9) 3 databases sizes 10gb, 100gb, 1TB how which database will take more time.

 10) You lost control file database is using RMAN backup with nocatalog. If you loose whole db as well same time how you recover database.

 11) what is sync, and async in standby how it works.

 12) Shut immediate is taking too much time how you diagnose what is the issue.

 13) How you take backup of OCR.

 14) What will happen if voting disk is down.

 15) What will happen if virtual IP is down in RAC.

 VIP – Virtual IP address in RAC VIP is mainly used for fast connection in failover. Until 9i RAC faileover we used physical IP address of another server. When the connection request come from a client to server, then failure of first server listener then RAC redirect the connection request to second available server using physical IP address. Hence it is physical IP address rediretion to second physical IP address is possible only after we get timeout error from First Physical IP address. So connection should wait a while for getting TCP connection timeout. From RAC 10g we can use the VIP to save connection timeout wait, Because ONS (Oracle Notification Service) maintains communication between each nodes and listeners. Once ONS found any listener down or node down, it will notify another nodes and listeners. While new connection is trying to establish connection to failure node or listener, virtual IP of failure node automatically divert to surviving node. This Process will not wait for TCP/IP timeout event. So new connection will be faster even one listener/node failed.