input/output size of rman backup different for disk/tape...

From: max scalf <oracle.blog3_at_gmail.com>
Date: Mon, 18 Apr 2016 21:16:01 +0000
Message-ID: <CAKoJ+qCKkD=bnzeeObrJcgDEas3ZvLo5yisj61h6AhPkiTUjdg_at_mail.gmail.com>

Hello all,

I am trying to figure out why i am seeing a different behaviour of rman with it comes to backup with regards to disk and tape. I have a DB size of about 732GB allocated and used is 600GB. When I ran an full rman backup to NFS input size is about 592.58G and output size is about 566.83G, i am getting the information using below query..When i ran the same rman backup, but this time going to SBT the input size is about 732.45G and output size is 620.01G. So I am trying to figure why the input/output size are different when it comes to backup for disk/tape...

SELECT b.session_key ses_key,

b.session_recid ses_recid,
b.session_stamp,
b.command_id,
b.input_type,
b.status,

to_char(b.start_time,'DD-MM-YY HH24:MI') "Start Time",

b.time_taken_display,
b.output_device_type device_type,
b.input_bytes_display,
b.output_bytes_display,
b.output_bytes_per_sec_display "OutBytesPerSec"

FROM v$rman_backup_job_details b
ORDER BY b.start_time asc;

*# Backup running to disk/NFS*
RUN
{
  ALLOCATE CHANNEL ch1 DEVICE TYPE DISK; .......
......
  ALLOCATE CHANNEL ch10 DEVICE TYPE DISK;   BACKUP check logical incremental level=0 CUMULATIVE FILESPERSET 1 FORMAT
'/backup/location_nfs/full_%u_%s_%p' DATABASE;
}

*## Backup running to tape *
RUN {
  ALLOCATE CHANNEL ch01 TYPE 'SBT_TAPE' PARMS
'ENV=(NB_ORA_POLICY=$NB_ORA_POLICY)';

......
......
  ALLOCATE CHANNEL ch10 TYPE 'SBT_TAPE' PARMS
'ENV=(NB_ORA_POLICY=$NB_ORA_POLICY)';

  BACKUP check logical incremental level=0 CUMULATIVE FILESPERSET 5 FORMAT
'full_%u_%s_%p' DATABASE;

  }

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Received on Mon Apr 18 2016 - 23:16:01 CEST