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Re: Compressing Rman Disk Backups

From: Tim Gorman <>
Date: Tue, 30 Mar 2004 06:07:25 -0700
Message-ID: <>

This functionality existed in RMAN9i, too (MetaLink note #167919.1).

Unfortunately, this functionality is only for "piping" the submission of RMAN commands into RMAN, not for the "piping" of backupsets or image-copies created by RMAN, which I believe was the original question of this thread...

I haven't been following this thread closely so I apologize if someone else has already addressed this, but...

...I personally don't think that Oracle is ever going to permit RMAN to write backupsets to named pipes or to the "stdout" output stream. In fact, the functionality of removing backupset files before writing to them is designed explicitly to prevent this from happening, is not a "bug", and will not be "corrected" in future. Now, I'm just dying to find out if I'm wrong already with RMAN10g... :-)

The reason is commercial -- I think that part of Oracle's agreement with tape-management software vendors is that there will be only two ways to store a backupset or image-copy with RMAN: DISK or SBT. They made this agreement in order to make RMAN a viable product; RMAN would not be viable without the support of tape-management software vendors, and those vendors won't put forth the effort to support RMAN unless they can make money from it. Allowing piping would permit a third method of taking backups that would completely negate the investment made by tape-management software vendors to develop an RMAN interface, or at least give customers a viable way to get backups to tape without buying the interface adapter. And you all know how much money they make from that interface, which is why everyone is trying to do piping...

Just my $0.02...

on 3/30/04 12:28 AM, Lex de Haan at wrote:

> from the 10g documentation:
> RMAN Pipe Interface
> ===================
> The RMAN pipe interface is an alternative method for issuing commands to
> RMAN and receiving the output from those commands. With this interface, RMAN
> obtains commands and sends output by using the DBMS_PIPE PL/SQL package.
> RMAN does not read or write any data using the operating system shell. By
> using this interface, it is possible to write a portable programmatic
> interface to RMAN.
> The pipe interface is invoked by using the PIPE command-line parameter. RMAN
> uses two private pipes: one for receiving commands and the other for sending
> output. The names of the pipes are derived from the value of the PIPE
> parameter. For example, you can invoke RMAN with the following command:
> % rman PIPE abc TARGET SYS/oracle_at_trgt
> RMAN opens the two pipes in the target database: ORA$RMAN_ABC_IN, which RMAN
> uses to receive user commands, and ORA$RMAN_ABC_OUT, which RMAN uses to send
> all output back to RMAN.
> All messages on both the input and output pipes are of type VARCHAR2.
> Note that RMAN does not permit the pipe interface to be used with public
> pipes, because they are a potential security problem. With a public pipe,
> any user who knows the name of the pipe can send commands to RMAN and
> intercept its output.
> See Also:
> "Executing RMAN Commands Through a Pipe" to learn how to execute RMAN
> commands through a pipe

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Received on Tue Mar 30 2004 - 07:03:29 CST

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