Re: GNU tar and PITR

Peter Eisentraut wrote:
> Am Montag, 16. Juli 2007 12:01 schrieb Peter Eisentraut:
> > http://developer.postgresql.org/pgdocs/postgres/continuous-archiving.html
> > says:
> >
> > """
> > Also, some versions of GNU tar consider it an error if a file is changed
> > while tar is copying it. There does not seem to be any very convenient way
> > to distinguish this error from other types of errors, other than manual
> > inspection of tar's messages. GNU tar is therefore not the best tool for
> > making base backups.
> > """
> >
> > However, GNU tar returns 2 for a real error and 1 for the file changed
> > case. Isn't that sufficient?
>
> Ah ...
>
> """
> version 1.16 - Sergey Poznyakoff, 2006-10-21
>
> * After creating an archive, tar exits with code 1 if some files were
> changed while being read.  Previous versions exited with code 2 (fatal
> error), and only if some files were truncated while being archived.
> """
>
> We should update the documentation.

Docs updated, patch attached.

--
  Bruce Momjian  <bruce@momjian.us>          http://momjian.us
  EnterpriseDB                               http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: backup.sgml
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RCS file: /cvsroot/pgsql/doc/src/sgml/backup.sgml,v
retrieving revision 2.98
retrieving revision 2.99
diff -c -r2.98 -r2.99
*** backup.sgml    29 Jun 2007 15:46:21 -0000    2.98
--- backup.sgml    16 Jul 2007 22:20:51 -0000    2.99
***************
*** 734,746 ****
      complaints of this sort from real errors.  For example, some versions
      of <application>rsync</> return a separate exit code for <quote>vanished
      source files</>, and you can write a driver script to accept this exit
!     code as a non-error case.  Also,
!     some versions of GNU <application>tar</> consider it an error if a file
!     is changed while <application>tar</> is copying it.  There does not seem
!     to be any very convenient way to distinguish this error from other types
!     of errors, other than manual inspection of <application>tar</>'s messages.
!     GNU <application>tar</> is therefore not the best tool for making base
!     backups.
     </para>

     <para>
--- 734,744 ----
      complaints of this sort from real errors.  For example, some versions
      of <application>rsync</> return a separate exit code for <quote>vanished
      source files</>, and you can write a driver script to accept this exit
!     code as a non-error case.  Also, some versions of GNU
!     <application>tar</> consider it an error if a file is changed while
!     <application>tar</> is copying it.  Fortunately, GNU
!     <application>tar</> versions 1.16 and later exit with <literal>1</>
!     if files changed during the backup, and <literal>2</> for other errors.
     </para>

     <para>