Allocate Channel ... Rate Not Working

From: Sam Bootsma <>
Date: Tue, 8 Jul 2008 17:06:42 -0400
Message-ID: <>

Hi All.  

We are running Oracle on AIX 5.3. We use an RMAN Catalog. On June 25 I ran the following RMAN script:  

$ cat dup_disk.rcv

spool log to '../logs/dup_disk.log';

run {

set until time "2008-06-25 7:00:00";

allocate auxiliary channel ch1 type DISK rate 512K;

allocate auxiliary channel ch2 type DISK rate 512K;

duplicate target database to PPRD;

release channel ch1;

release channel ch2;


spool log off  

Prior to running this script I had set appropriate environment variables and connections to the RMAN catalog and target and auxiliary databases.  

I was expecting this to duplicate my database at rate of 1 MB per second. But, the job had to be killed because it was killing performance. After about 50 minutes it had restored 47.68 GB worth of data files. When I did calculations, this came to 16.19 MB per seconds!!!  

Can anybody tell me why? Am I doing something wrong?  

I did check the documentation, and in one spot it said: "Set limits on I/O bandwidth consumption in kilobytes, megabytes, or gigabytes (ALLOCATE CHANNEL ... RATE, CONFIGURE CHANNEL ... RATE) "  

And in another location the documentation said:


in release old syntax
preferred current syntax

9.0.1 ALLOCATE CHANNEL ... READRATE CONFIGURE CHANNEL ... RATE   My understanding of deprecate is that Oracle will not longer maintain or fix problems related to the deprecated item. Is that what has happened here? Could the underlying code have changed sufficiently that the rate command no longer works with Allocate channel? Or does the problem lie elsewhere?  

Thanks for any suggestions.  


Sam Bootsma

Oracle Database Administrator

Information Technology Services
George Brown College

Phone: 416-415-5000 x4933
Fax: 416-415-4836
E-mail: <>  

Received on Tue Jul 08 2008 - 16:06:42 CDT

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