I am trying to run an RMAN backup that is either hung or is taking a very long time. Some background:

  • I inherited this database, and I am unfamiliar with Oracle, as I am an SQL Server guy, so please point out / forgive any basic gaps in my knowledge
  • This database is large but infrequently-used, and is loaded up with external data for analysis. There are no transactions. Therefore, the database is in NOARCHIVELOG mode.
  • I need to do a one-time backup for now, so I think I don't need a recovery catalog.
  • I'm not quite sure of the database size, but it is on the order of 1TB

Here's what I did, cobbled together from various sources on the internet:

> rman target mydatabase

startup mount;
run {
    allocate channel ch1 device type disk format 'C:/Backup_Folder/%U';
    backup format 'C:/Backup_Folder/db_%t_%s.bk' (database);
    release channel ch1;

The backup seems to be stuck on channel ch1: starting piece 1 at 01-MAY-15

RMAN creates a tiny (90K) file in C:/Backup_Folder but then nothing else has happened for over an hour. Do I just wait? Am I doing something wrong?

  • Can you see RMAN session in v$session_longops?
    – elfcheg
    May 6, 2015 at 8:25

1 Answer 1


Don't specify two conflicting FORMATs (you have one in the ALLOCATE CHANNEL command and one in the BACKUP command).

If and when you need different FORMATs (e.g. one for database datafile backups, one for archivelog backups and one for controlfile backups) specify them explicitly with the BACKUP command.


> rman target mydatabase

    startup mount;
        DISK FORMAT 'C:\Backup_Folder\mydatabase%d_DB_%u_%s_%p'; 

Note: I noticed that you provided the path starting with "C:/". Shouldn't it start with "C:\"?

  • You need to look at the alert log. If you are using 10g or before you need to look at background_dump_dest, otherwise you need to look at diag and it would be in <diag dir>\diag\rdbms\<sidname>\<sidname>\trace. Also run the rman utility, proably from dos,connect target to the database and do "show all;". There could be an issue with autobackup or snapshot of the control file.
    – Gandolf989
    May 5, 2015 at 17:09

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