12cR1 RAC Posts — 6 :Running the Cluster Verification Utility

With a successful RAC Cluster, running the Cluster Verification Utility [oracle@collabn1 ~]$ cluvfy stage -post crsinst -n collabn1,collabn2Performing post-checks for cluster services setupChecking node reachability...Node reachability check passed from node "collabn1"Checking user equivalence...User equivalence check passed for user "oracle"Checking node connectivity...Checking hosts config file...Verification of the hosts config file successfulCheck: Node connectivity using interfaces on subnet "192.168.78.0"Node connectivity passed for subnet "192.168.78.0" with node(s) collabn2,collabn1TCP connectivity check passed for subnet "192.168.78.0"Check: Node connectivity using interfaces on subnet "172.16.100.0"Node connectivity passed for subnet "172.16.100.0" with node(s) collabn1,collabn2TCP connectivity check passed for subnet "172.16.100.0"Checking subnet mask consistency...Subnet mask consistency check passed for subnet "192.168.78.0".Subnet mask consistency check passed for subnet "172.16.100.0".Subnet mask consistency check passed.Node connectivity check passedChecking multicast communication...Checking subnet "172.16.100.0" for multicast communication with multicast group "224.0.0.251"...Check of subnet "172.16.100.0" for multicast communication with multicast group "224.0.0.251" passed.Check of multicast communication passed.Checking whether the ASM filter driver is active and

Undo and Redo

Quick and Rough Notes : Undo and RedoUndo is where Oracle logs how to reverse a transaction (one or more DMLs in a transaction)Redo is where Oracle logs how to replay a transactionUndo and Redo are written to as the transaction proceeds, not merely at the end of the transaction(imagine a transaction that consists of 1million single-row inserts, each distinct insert is written to undo and redo) Undo segmentsOracle dynamically creates and drops Undo segments depending on transaction volumeAn undo segment consists of multiple extents.