Skip to content
pvmehta.com

pvmehta.com

  • Home
  • About Me
  • Toggle search form
  • Good RAC & Standby Notes Oracle
  • Adding addidional hard drive and attach it to a linux box. Linux/Unix
  • Free conference number from http://www.freeconference.com Oracle
  • Jai Shree Ram Oracle
  • Wait time tuning research Oracle
  • Korn Shell Arithmatic Linux/Unix
  • CTAS with LONG Column for 7.x and 8 and 8i Oracle
  • Important Solaris Commands Linux/Unix
  • Processes Parameter decision Oracle
  • S3 Basic info AWS
  • Rollback force for distributed transactions Oracle
  • sid_wise_sql.sql Further explaination Oracle
  • TABLE SIZING WITH DB_BLOCK ARCHITECTURE Reference : Metalink note : 10640.1 Oracle
  • secure crt settings Linux/Unix
  • Oracle Identifiers Oracle

Difference between SYNC and AFFIRM

Posted on 27-Jan-2010 By Admin No Comments on Difference between SYNC and AFFIRM

LGWR SYNC AFFIRM in Oracle Data Guard is used for zero data loss. How does one ensure zero data loss? Well, the redo block generated at the primary has to reach the standby across the network (that’s where the SYNC part comes in – i.e. it is a synchronous network call), and then the block has to be written on disk on the standby (that’s where the AFFIRM part comes in) – typically on a standby redo log.

Can you have LGWR SYNC NOAFFIRM? Yes sure. Then you will have synchronous network transport, but the only thing you are guaranteed is that the block has reached the remote standby’s memory. It has not been written on to disk yet. So not really a zero data loss solution (e.g. what if the standby instance crashes before the disk I/O).

To sum up -> LGWR SYNC AFFIRM means primary transaction commits are waiting for ntk I/O + disk I/O acks. LGWR SYNC NOAFFIRM means primary transaction commits are waiting for ntk I/O only.

Oracle, rman-dataguard

Post navigation

Previous Post: useful dg links
Next Post: oracle fast start failover best practice

Related Posts

  • Find_stale_dr.sql finding stale physical DR.. Oracle
  • Multiple listeners Oracle
  • Changing the Global Database Name Oracle
  • eplan9i.sql Oracle
  • Is It Recommended To Apply Patch Bundles When PSU Is Available? -ID 743554.1 Oracle
  • Jai Shree Ram Oracle

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Categories

  • AWS (2)
  • Azure (1)
  • Linux/Unix (149)
  • Oracle (388)
  • PHP/MYSQL/Wordpress (10)
  • Power-BI (0)
  • Python/PySpark (7)
  • RAC (17)
  • rman-dataguard (26)
  • shell (149)
  • SQL scripts (337)
  • Uncategorized (0)
  • Videos (0)

Recent Posts

  • findinfo.sql (SQL for getting CPU and Active session info)27-May-2025
  • SQL Tracker by SID sqltrackerbysid.sql22-Apr-2025
  • How to connect to Oracle Database with Wallet with Python.21-Mar-2025
  • JSON/XML Types in Oracle18-Mar-2025
  • CPU Core related projections12-Mar-2025
  • Exadata Basics10-Dec-2024
  • Reading config file from other folder inside class24-Sep-2024
  • Python class import from different folders22-Sep-2024
  • Transfer SQL Profiles from One database to other database.05-Sep-2024
  • Load testing on Oracle 19C RAC with HammerDB18-Jan-2024

Archives

  • 2025
  • 2024
  • 2023
  • 2010
  • 2009
  • 2008
  • 2007
  • 2006
  • 2005
  • How To Resolve Stranded DBA_2PC_PENDING Entries ID 401302.1 (Very Good prooven) Oracle
  • Sequence Resetting Oracle
  • Oracle 11g Environment Setup Oracle
  • login.sql Oracle
  • Some useful Unix Commands Linux/Unix
  • Jai Shree Ram Oracle
  • Unix split command to split files Linux/Unix
  • Search and Replace vi editor command. Linux/Unix

Copyright © 2025 pvmehta.com.

Powered by PressBook News WordPress theme