Khurram Siddiqui

I am an IT professional with 10 years of professional experience,I have good proficiency on Oracle technologies, and at last 2 years of my career to study Real Application Clusters,data guard and participate actively on Oracle community ,If you want to hire me on Contract or to quote on project basis contact me at khurrampc@hotmail.com.

Monday, October 12, 2009

Recovery Window

Setting RMAN recovery window to 2 days make any backup older than 2 days become obsolete is a myth. See below the scenario which make you understand what need to consider when you are setting RMAN recovery window.
For Non Incremental Level backup
================================

Assume no backup exist before 13th of Oct
Assume recovery window is 2
POR = Point of recoverability

-----------------------------------------------------------------------------------------------------------
date           backup type        status               POR (Current date-recovery window)
-----------------------------------------------------------------------------------------------------------
13-OCT-2009    Full backup        No obsolete found    13-OCT-2009-2 = 11-OCT-2009
15-OCT-2009    Full backup        No obsolete found    15-OCT-2009-2 = 13-OCT-2009
16-OCT-2009    Full backup        No obsolete found    16-OCT-2009-2 = 14-OCT-2009
See above table data on 16-OCT-2009 , POR is 14-OCT-2009 and you dont have any backup on 14th of oct within yours backup schedule, in this case 13th Oct backup will enable you POR of 14th Oct , 13th Oct backup will not be marked obsoleted What would be happen on 17th of october lets see
-----------------------------------------------------------------------------------------------------------
date           backup type        status               POR (Current date-recovery window=POR)
-----------------------------------------------------------------------------------------------------------
13-OCT-2009    Full backup        No obsolete found    13-OCT-2009-2 = 11-OCT-2009
15-OCT-2009    Full backup        No obsolete found    15-OCT-2009-2 = 13-OCT-2009
16-OCT-2009    Full backup        No obsolete found    16-OCT-2009-2 = 14-OCT-2009
17-OCT-2009    No   backup        13th Oct Full backup 17-OCT-2009-2 = 15-OCT-2009
                                  will be marked 
                                  obsoleted
See above table data on 17-OCT-2009 , POR is 15-OCT-2009 you have backup on 15th of oct within yours backup schedule, in this case 13th Oct backup will not be needed for the point of recoverability for 15th of Oct ,15th Oct backup already exist for the POR,15th Oct backup will provide you POR and hence 13th Oct backup will be marked obsoleted.
For Incremental Level backup
================================

Assume no backup exist before 13th of Oct
Assume recovery window is 2
POR = Point of recoverability

-----------------------------------------------------------------------------------------------------------
date           backup type   status               POR (Current date-recovery window)
-----------------------------------------------------------------------------------------------------------
13-OCT-2009    L0            No obsolete found    13-OCT-2009-2 = 11-OCT-2009
14-OCT-2009    L1            No obsolete found    14-OCT-2009-2 = 12-OCT-2009
15-OCT-2009    L1            No obsolete found    15-OCT-2009-2 = 13-OCT-2009
16-OCT-2009    L1            No obsolete found    16-OCT-2009-2 = 14-OCT-2009
See above table data on 16-OCT-2009 , POR is 14-OCT-2009 you have backup on 14th of oct within yours backup schedule but this backup is L1 not L0 , in this case 13th Oct backup will be needed for the point of recoverability for 14th of Oct ,13th Oct backup will not be marked obsoleted.
-----------------------------------------------------------------------------------------------------------
date           backup type   status               POR (Current date-recovery window)
-----------------------------------------------------------------------------------------------------------
13-OCT-2009    L0            No obsolete found    13-OCT-2009-2 = 11-OCT-2009
14-OCT-2009    L1            No obsolete found    14-OCT-2009-2 = 12-OCT-2009
15-OCT-2009    L1            No obsolete found    15-OCT-2009-2 = 13-OCT-2009
16-OCT-2009    L1            No obsolete found    16-OCT-2009-2 = 14-OCT-2009
17-OCT-2009    L1            No obsolete found    17-OCT-2009-2 = 15-OCT-2009
See above table data on 17-OCT-2009 , POR is 15-OCT-2009 you have backup on 15th of oct within yours backup schedule but this backup is L1 not L0 , in this case 13th Oct backup will be needed for the point of recoverability for 15th of Oct ,13th Oct backup will not be marked obsoleted yet.
-----------------------------------------------------------------------------------------------------------
date           backup type   status               POR (Current date-recovery window)
-----------------------------------------------------------------------------------------------------------
13-OCT-2009    L0            No obsolete found    13-OCT-2009-2 = 11-OCT-2009
14-OCT-2009    L1            No obsolete found    14-OCT-2009-2 = 12-OCT-2009
15-OCT-2009    L1            No obsolete found    15-OCT-2009-2 = 13-OCT-2009
16-OCT-2009    L1            No obsolete found    16-OCT-2009-2 = 14-OCT-2009
17-OCT-2009    L1            No obsolete found    17-OCT-2009-2 = 15-OCT-2009
18-OCT-2009    L1            No obsolete found    18-OCT-2009-2 = 16-OCT-2009
19-OCT-2009    L1            No obsolete found    19-OCT-2009-2 = 17-OCT-2009
20-OCT-2009    L0            No obsolete found    20-OCT-2009-2 = 18-OCT-2009
21-OCT-2009    No backup     No obsolete found    21-OCT-2009-2 = 19-OCT-2009
22-OCT-2009    No backup     obsolete found       22-OCT-2009-2 = 20-OCT-2009
                             13th L0 and its 
                             alls L1 
See above table data on 22-OCT-2009 , POR is 20-OCT-2009 you have L0 backup on 20th of oct within yours backup schedule and this backup is L0 not L1 , in this case 20th Oct backup will be needed for the point of recoverability for 20th of Oct ,before 20th L0 backup 13th L0 backup will marked obsoleted and hence alls its incremental level backup will be marked obsoleted.

Followers

About Me

My Photo
Melbourne, Victoria, Australia