Re: Restore/Duplicate takes a lot longer to restore than backup

  • From: Michael Fontana <michael.fontana@xxxxxxxxxxx>
  • To: howard latham <howard.latham@xxxxxxxxx>
  • Date: Wed, 6 Jan 2010 14:12:30 -0600 (CST)

Depending upon the version/release/patch level of your Oracle software, the 
number of channels you
can dedicate to the process, and the mix of jobs running, there is a great 
variance in recovery time.

Things improved greatly from to, and there are some good 
patches dealing with decompression in  

There are also new options to speed up recovery times by varying compression 
algorithms in 11g, but alas,
a compressed backupset will always take longer to recover because of the extra 
steps involved.

----- Original Message -----
From: "Howard Latham" <howard.latham@xxxxxxxxx>
To: JBECKSTROM@xxxxxxxxx
Cc: "oracle-l-freelists" <oracle-l@xxxxxxxxxxxxx>, "oracle-db-l" 
Sent: Wednesday, January 6, 2010 1:53:51 PM GMT -06:00 US/Canada Central
Subject: Re: Restore/Duplicate takes a lot longer to restore than backup

We have found that the compression causes the restore to take MUCH
MUCH MUCH longer. It seems that the decompression  algorithm is very
slow. WE abandoned compression so we could get a database back quicker
- 3 hours instead of 18.

On 06/01/2010, Jeffrey Beckstrom <JBECKSTROM@xxxxxxxxx> wrote:
> We are doing a compressed backup of a 200G database in about 2 hours.  When
> we run the duplicate command, we copy the production backup files to the
> local disks of the target server.  We then run the RMAN duplicate command
> and it takes over 6 hours.  Is it reasonable that a restore/duplicate from a
> compressed backup takes that much longer than the actual backup?  Is there
> anything that can be done to speed up the process?
> Jeffrey Beckstrom
> Database Administrator
> Greater Cleveland Regional Transit Authority
> 1240 W. 6th Street
> Cleveland, Ohio 44113

Howard A. Latham


Michael Fontana 

Sr. Technical Consultant 

Enkitec M: 214.912.3709 




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