Skip to main content

Types of Backups in RMAN

RMAN is very flexible and it offers many different types of backups.  We need to start with a list of backup types:
·         Full backup:  A full backup backs up all data files in the database, block-by-block, a standalone backup with everything you need to recover to the point in time when the full backup was collected.

·         Level 1 backup:  A level 1 backup includes only those blocks that have been changed since the “parent” backup was taken. Remember a parent backup may be either a level 0 or a level 1 backup.

·         Level 0 backup:  A level 0 incremental backup is physically identical to a full backup and it includes every data block in the file except empty blocks. The only difference is that the level 0 backup is recorded as an incremental backup in the RMAN repository, so it can be used as the parent for a level 1 backup.
·         Incremental backup:  An incremental backup can be either level 0 or level 1.
There are two types of incremental backups, “differential” and “cumulative”.  See my full notes on incremental differential vs. incremental cumulative backups.

·         Differential Incremental Backup:  When using differential incremental backup (the default type of incremental backup), RMAN looks for changed data blocks which were changed after last level 1 incremental backup. It there’s no level 1 backup made before it, it takes a backup of the changed data blocks which were made after level 0 incremental backup. 
·         Cumulative Incremental Backup:  In a cumulative incremental backup RMAN takes backup of all changed data blocks after level 0 or level 1 incremental backup.  Like a differential backup, incremental backups also back up only the changed data blocks, but an incremental backup only backs up the data that has changed since the last backup.  If the last backup was also an incremental backup, the current incremental backups only records “changes to the changes”, a much smaller set of block changes, and hence, a much smaller recovery time than a differential backup.
Labels:

Comments

Post a Comment

Popular posts from this blog

Java Sample: While loop

public class whilechk1 {     public static void main(String args[])     {         int row,column,y;         System.out.print("\nMultiplication Table\n");         row=1;         do         {             column=1;             do             {                 y=row*column;                 System.out.print("\t"+y);                 column++;             }while(column<=10);             System.out.println("\n");             row++;         }while(row<=10);     } }
Post a Comment
Read more

A Hit Count Using Java Servlet's Session Tracking

import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class SessionTracker extends HttpServlet {         public void doGet(HttpServletRequest req,HttpServletResponse res)         throws ServletException,IOException         {                res.setContentType("text/html");                PrintWriter out=res.getWriter();                HttpSession session=req.getSession(true);                Integer count=(Integer)session.getValue("tracker.count");                if(count==null)       ...
2 comments
Read more

Background Process in ORACLE Database

Background Process in ORACLE Database Database Writer Process (DBWn) Log Writer Process (LGWR) Checkpoint Process (CKPT) System Monitor Process (SMON) Process Monitor Process (PMON) Recoverer Process (RECO) Job Queue Processes Archiver Processes (ARCn) Queue Monitor Processes (QMNn) Database Writer Process (DBWn) The database writer process (DBWn) writes the contents of buffers to datafiles. The DBWn processes are responsible for writing modified (dirty) buffers in the database buffer cache to disk. Although one database writer process (DBW0) is adequate for most systems, you can configure additional processes (DBW1 through DBW9 and DBWa through DBWj) to improve write performance if your system modifies data heavily. These additional DBWn processes are not useful on uniprocessor systems. When a buffer in the database buffer cache is modified, it is marked dirty. A cold buffer is a buffer that has not been recently used according to the least recently used (LRU) algorith...
Post a Comment
Read more