I am running Oracle 11g R2 single instance on Linux 6.7.
Data guard is also configured.

In a database I have 4 groups of redologs, each group has 2 members and each logfile size is 200mb.

The problem I am facing is that LGWR is switching every 4 minutes. The output size of archivelogs are maximum 90mb to 100mb.

What should I do to solve this problem?


1 Answer 1


The output size of archivelogs are maximum 90mb to 100mb.

Its not necessary to have archived log file should be same.

during night session logs get filled upto 180mb out of 200mb. but during morning session logs get maximum to 90mb to 100mb

Its not necessary to have log switch occur when online redo log file is 100% full. There is also an algorithm inside Oracle which determines the timing for the log switch.
After the log switch, the archiver process will copy only the actual information from the redo log files. Since the redo logs are not 100% full after the log switch this results in uneven, smaller files than the original redo log files.

Some of the factors which may enforce frequent log switch are listed below:

  • Online redo log file size
  • LOG_BUFFER_SIZE parameter.
  • Current load of the database
  • Logfile space reservation algorithm

    Details are given in an Oracle knowledge based document.(MOS account required) Archived redolog is (significant) smaller than the redologfile. (Doc ID 1356604.1)

  • 1
    • LGWR switching every 4 minutes ... hmmm why is that a problem? however if it is switching that fast, you might want to add another 4-8 redolog groups so you have enough breathing room between switching a log and arch writing..
      – Raj
      Mar 16, 2016 at 13:08

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