Re: data=writeback - Mailing list pgsql-performance

From Chris
Subject Re: data=writeback
Date
Msg-id 1081414889.5037.29.camel@dell
Whole thread Raw
In response to data=writeback  ("Priem, Alexander" <ap@cict.nl>)
List pgsql-performance
> LABEL=/usr/local/pgsql  /usr/local/pgsql      ext3
> noatime,data=writeback  1 2
> LABEL=/usr/local/pgsql  /usr/local/pgsql/wal  ext3
> noatime,data=ordered    1 2

The same label mounted on two different mount points is probably I typo?

I'm not sure if data=writeback is ok. I was wondering about the same
thing after reading the "good pc but bad performance,why?" thread.

This is from man mount:

  writeback
  Data ordering is not preserved - data may be written into
  the  main file system after its metadata has been commit-
  ted to the journal.  This is rumoured to be the  highest-
  throughput  option.   It  guarantees internal file system
  integrity, however it can allow old  data  to  appear  in
  files after a crash and journal recovery.

How does this relate to fflush()? Does fflush still garantee
all data has ben written?

Bye, Chris.



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