xtrabackup --prepare prints a few lines to stdout

[Henrik Ingo]

Related to the --stream feature of xtrabackup, it is designed to print any informational output to stderr. Also when not using --stream, this seems to be the case.

I like to run xtrabackup with 2>, ie I redirect the stderr output into a log file.

If I use
  XTRABACKUP=xtrabackup_51
  $XTRABACKUP --prepare --apply-log-only --target-dir=$APPLY_DIR 2>> $APPLY_DIR/$BACKUPNAME.log
or
  $XTRABACKUP --prepare --target-dir=$READY_DIR 2>> $READY_DIR/$BACKUPNAME.log

then the following lines still appear on the console, ie they seem to be output to stdout:

**
xtrabackup_51 Ver 1.5 Rev 203 for 5.1.52 pc-linux-gnu (i686)
xtrabackup: xtrabackup_logfile detected: size=2097152, start_lsn=(0 21013878)

[notice (again)]
  If you use binary log and don't use any hack of group commit,
  the binary log position seems to be:
**

It would be nicer if everything went consistently to stderr.

[Henrik Ingo (hingo)]

Similarly, when doing an incremental backup:

  $XTRABACKUP --backup --target-dir=$INC --incremental-basedir=$APPLY_DIR 2>>$INC/$BACKUPNAME.log

I get these lines in stderr/the log file:

xtrabackup: uses posix_fadvise().
xtrabackup: cd to /var/lib/mysql
xtrabackup: Target instance is assumed as followings.
xtrabackup: innodb_data_home_dir = ./
xtrabackup: innodb_data_file_path = ibdata1:10M:autoextend
xtrabackup: innodb_log_group_home_dir = ./
xtrabackup: innodb_log_files_in_group = 2
xtrabackup: innodb_log_file_size = 5242880
>> log scanned up to (0 21014228)
>> log scanned up to (0 21014228)

And these lines in stdout/console:

xtrabackup_51 Ver 1.5 Rev 203 for 5.1.52 pc-linux-gnu (i686)
incremental backup from 0:21013878 is enabled.
[01] Copying ./ibdata1
     to //data/backups/hingo-nokia-vm/12/inc1/ibdata1.delta
[01] ...done
xtrabackup: The latest check point (for incremental): '0:21014228'
xtrabackup: Stopping log copying thread.
xtrabackup: Transaction log of lsn (0 21014228) to (0 21014228) was copied.