12cR1 RAC Posts — 8b : DUPLICATE DATABASE FOR STANDBY

Continuing the previous post, where I have done the pre-setup…(A reminder : This is a SingleInstance Standby on FileSystem for a RAC Database with a PDB on ASM) On the SingleInstance Node (for the Standby database) Precreate the required folders for the database (and redo and control) files (I later realised that the “onlinelog” folders for the SEED and PDB are not required) [oracle@oem132 ~]$ cd /u01/app/oracle/oradata[oracle@oem132 oradata]$ mkdir STBY[oracle@oem132 oradata]$ cd STBY[oracle@oem132 STBY]$ mkdir datafile[oracle@oem132 STBY]$ mkdir onlinelog[oracle@oem132 STBY]$ mkdir 44bbc69ce8f552aee053334ea8c07365[oracle@oem132 STBY]$ mkdir fd9ac20f64d244d7e043b6a9e80a2f2f[oracle@oem132 STBY]$ cd 44*[oracle@oem132 44bbc69ce8f552aee053334ea8c07365]$ mkdir datafile tempfile[oracle@oem132 44bbc69ce8f552aee053334ea8c07365]$ cd ../fd*[oracle@oem132 fd9ac20f64d244d7e043b6a9e80a2f2f]$ mkdir datafile tempfile[oracle@oem132 fd9ac20f64d244d7e043b6a9e80a2f2f]$[oracle@oem132 STBY]$[oracle@oem132 STBY]$ cd /u01/app/oracle/fast_recovery_area[oracle@oem132 fast_recovery_area]$ mkdir STBY[oracle@oem132 fast_recovery_area]$ cd STBY[oracle@oem132 STBY]$ mkdir onlinelog[oracle@oem132 STBY]$ mkdir 44bbc69ce8f552aee053334ea8c07365[oracle@oem132 STBY]$ mkdir fd9ac20f64d244d7e043b6a9e80a2f2f[oracle@oem132 STBY]$ cd 44*[oracle@oem132 44bbc69ce8f552aee053334ea8c07365]$ mkdir onlinelog[oracle@oem132 44bbc69ce8f552aee053334ea8c07365]$ cd ../fd*[oracle@oem132 fd9ac20f64d244d7e043b6a9e80a2f2f]$ mkdir onlinelog[oracle@oem132 fd9ac20f64d244d7e043b6a9e80a2f2f]$[oracle@oem132 STBY]$ Note that the names of the two folders for the SEED and the PDB are in *lower

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.