RE: RMAN backup - basic Qs

2003-01-17 Thread Mercadante, Thomas F
I stand corrected.

thanks Robert.

Tom Mercadante
Oracle Certified Professional


-Original Message-
Sent: Thursday, January 16, 2003 3:20 PM
To: Multiple recipients of list ORACLE-L


RMAN does no compression on any blocks with data. The only compression that
occurs that blocks above the HWM are not included. No compression of data
occurs, and in fact empty blocks can and are backed up by RMAN.

RF

Robert G. Freeman 
Technical Management Consultant
TUSC - The Oracle Experts www.tusc.com
904.708.5076 Cell (it's everywhere that I am!)
Author of several books you can find on Amazon.com!



-Original Message-
Sent: Thursday, January 16, 2003 1:54 PM
To: Multiple recipients of list ORACLE-L


No.  

Because Rman is not placing the tablespaces in a HOT BACKUP mode.  Rman is
simply reading the blocks, compressing them, and writing them to tape.

Tom Mercadante
Oracle Certified Professional


-Original Message-
Sent: Thursday, January 16, 2003 12:35 PM
To: Multiple recipients of list ORACLE-L



Is Excessive Redo Generated during RMAN OPEN Database backup using backup
sets as happens in case of HOT Backup ?

If NOT , Why ?

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RE: RMAN backup - basic Qs

2003-01-17 Thread Deshpande, Kirti
Also, RMAN can do incremental backups, copying only the blocks that changed since last 
backup. More about all this in Oracle Manuals and in Robert's book.  

- Kirti 

-Original Message-
Sent: Thursday, January 16, 2003 10:04 PM
To: Multiple recipients of list ORACLE-L


Maria - Definitely faster. Often hot backups can generate additional redo.

Dennis Williams
DBA, 40%OCP
Lifetouch, Inc.
[EMAIL PROTECTED] 


-Original Message-
Sent: Thursday, January 16, 2003 9:24 PM
To: Multiple recipients of list ORACLE-L


does this make RMAN hot backups faster or slower than when backing up file
in
backup mode?

[EMAIL PROTECTED] wrote:

 To better answer the original question, my understanding of this
difference
 is as under:

 Why do you put the tablespace in backup mode during normal hot backups
 without RMAN? This is to avoid backing up split blocks. Say, you have a
 database with a block size of 16K. And that a block is in the process of
 being backed up, with reads happening in chunks of say, 512 bytes.  Assume
 a user transaction updates this block while the backup is in progress.
This
 could result in an inconsistent version of the block being backed up, or
 what is called as split blocks.  Putting a tablespace in backup mode, is
 primarily, a flag which tells Oracle to copy the entire block into the
redo
 stream, and not just the changed vectors or deltas, which it would have
 done otherwise. This is so that, in case of recovery, the entire block can
 be read from the redo stream, and applied. Hence, this results in an
 increase in the redo size during normal hot backups.

 RMAN however, does not place the tablespaces in hot backup mode.  They use
 the same read consistency mechanism used by the SQL statements. Hence, no
 excessive redo is generated.

 Hope this helps.

 Raj

 Original Message-
 Sent: Thursday, January 16, 2003 1:54 PM
 To: Multiple recipients of list ORACLE-L

 Rman uses the same construct to get the right data in a hot backup as
 sqlplus, the SCN of the database. It reduces excess redo because you don't
 have to put the datafile in backup mode with a begin backup and take it
out

 with and end backup.

 HTH,
 Ruth
 - Original Message -
 To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
 Sent: Thursday, January 16, 2003 12:35 PM

 
  Is Excessive Redo Generated during RMAN OPEN Database backup using
backup

 sets as happens in case of HOT Backup ?
 
  If NOT , Why ?
 
  --
  Please see the official ORACLE-L FAQ: http://www.orafaq.net
  --
  Author: VIVEK_SHARMA
INET: [EMAIL PROTECTED]

 --
 Please see the official ORACLE-L FAQ: http://www.orafaq.net
 --
 


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RE: RMAN backup - basic Qs

2003-01-16 Thread Mercadante, Thomas F
No.  

Because Rman is not placing the tablespaces in a HOT BACKUP mode.  Rman is
simply reading the blocks, compressing them, and writing them to tape.

Tom Mercadante
Oracle Certified Professional


-Original Message-
Sent: Thursday, January 16, 2003 12:35 PM
To: Multiple recipients of list ORACLE-L



Is Excessive Redo Generated during RMAN OPEN Database backup using backup
sets as happens in case of HOT Backup ?

If NOT , Why ?

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: VIVEK_SHARMA
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Re: RMAN backup - basic Qs

2003-01-16 Thread Ruth Gramolini
Rman uses the same construct to get the right data in a hot backup as
sqlplus, the SCN of the database. It reduces excess redo because you don't
have to put the datafile in backup mode with a begin backup and take it out
with and end backup.

HTH,
Ruth
- Original Message -
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Thursday, January 16, 2003 12:35 PM



 Is Excessive Redo Generated during RMAN OPEN Database backup using backup
sets as happens in case of HOT Backup ?

 If NOT , Why ?

 --
 Please see the official ORACLE-L FAQ: http://www.orafaq.net
 --
 Author: VIVEK_SHARMA
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RE: RMAN backup - basic Qs

2003-01-16 Thread Freeman Robert - IL
RMAN does no compression on any blocks with data. The only compression that
occurs that blocks above the HWM are not included. No compression of data
occurs, and in fact empty blocks can and are backed up by RMAN.

RF

Robert G. Freeman 
Technical Management Consultant
TUSC - The Oracle Experts www.tusc.com
904.708.5076 Cell (it's everywhere that I am!)
Author of several books you can find on Amazon.com!



-Original Message-
Sent: Thursday, January 16, 2003 1:54 PM
To: Multiple recipients of list ORACLE-L


No.  

Because Rman is not placing the tablespaces in a HOT BACKUP mode.  Rman is
simply reading the blocks, compressing them, and writing them to tape.

Tom Mercadante
Oracle Certified Professional


-Original Message-
Sent: Thursday, January 16, 2003 12:35 PM
To: Multiple recipients of list ORACLE-L



Is Excessive Redo Generated during RMAN OPEN Database backup using backup
sets as happens in case of HOT Backup ?

If NOT , Why ?

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: VIVEK_SHARMA
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RE: RMAN backup - basic Qs

2003-01-16 Thread Chris Stephens
Title: RE: RMAN backup - basic Qs





what happens when a 'snapshot too old' situation occurs??...how can RMAN produce a valid backup in that case?


many i'm missing something.


-Original Message-
From: Ruth Gramolini [mailto:[EMAIL PROTECTED]]
Sent: Thursday, January 16, 2003 1:54 PM
To: Multiple recipients of list ORACLE-L
Subject: Re: RMAN backup - basic Qs



Rman uses the same construct to get the right data in a hot backup as
sqlplus, the SCN of the database. It reduces excess redo because you don't
have to put the datafile in backup mode with a begin backup and take it out
with and end backup.


HTH,
Ruth
- Original Message -
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Thursday, January 16, 2003 12:35 PM




 Is Excessive Redo Generated during RMAN OPEN Database backup using backup
sets as happens in case of HOT Backup ?

 If NOT , Why ?

 --
 Please see the official ORACLE-L FAQ: http://www.orafaq.net
 --
 Author: VIVEK_SHARMA
 INET: [EMAIL PROTECTED]

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RE: RMAN backup - basic Qs

2003-01-16 Thread Jared . Still
Maybe you could explain why you think ORA-1550 is related to backups?

It isn't, but you have some misconception about it to clear up.

Jared






Chris Stephens [EMAIL PROTECTED]
Sent by: [EMAIL PROTECTED]
 01/16/2003 01:19 PM
 Please respond to ORACLE-L

 
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
cc: 
Subject:RE: RMAN backup - basic Qs


what happens when a 'snapshot too old' situation occurs??...how can RMAN 
produce a valid backup in that case? 
many i'm missing something. 
-Original Message- 
Sent: Thursday, January 16, 2003 1:54 PM 
To: Multiple recipients of list ORACLE-L 

Rman uses the same construct to get the right data in a hot backup as 
sqlplus, the SCN of the database. It reduces excess redo because you don't 
have to put the datafile in backup mode with a begin backup and take it 
out 
with and end backup. 
HTH, 
Ruth 
- Original Message - 
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] 
Sent: Thursday, January 16, 2003 12:35 PM 

 
 Is Excessive Redo Generated during RMAN OPEN Database backup using 
backup 
sets as happens in case of HOT Backup ? 
 
 If NOT , Why ? 
 
 -- 
 Please see the official ORACLE-L FAQ: http://www.orafaq.net 
 -- 
 Author: VIVEK_SHARMA 
   INET: [EMAIL PROTECTED] 
 
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RE: RMAN backup - basic Qs

2003-01-16 Thread Rajesh . Rao

To better answer the original question, my understanding of this difference
is as under:

Why do you put the tablespace in backup mode during normal hot backups
without RMAN? This is to avoid backing up split blocks. Say, you have a
database with a block size of 16K. And that a block is in the process of
being backed up, with reads happening in chunks of say, 512 bytes.  Assume
a user transaction updates this block while the backup is in progress. This
could result in an inconsistent version of the block being backed up, or
what is called as split blocks.  Putting a tablespace in backup mode, is
primarily, a flag which tells Oracle to copy the entire block into the redo
stream, and not just the changed vectors or deltas, which it would have
done otherwise. This is so that, in case of recovery, the entire block can
be read from the redo stream, and applied. Hence, this results in an
increase in the redo size during normal hot backups.

RMAN however, does not place the tablespaces in hot backup mode.  They use
the same read consistency mechanism used by the SQL statements. Hence, no
excessive redo is generated.

Hope this helps.

Raj



Original Message-
Sent: Thursday, January 16, 2003 1:54 PM
To: Multiple recipients of list ORACLE-L





Rman uses the same construct to get the right data in a hot backup as
sqlplus, the SCN of the database. It reduces excess redo because you don't
have to put the datafile in backup mode with a begin backup and take it out

with and end backup.


HTH,
Ruth
- Original Message -
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Thursday, January 16, 2003 12:35 PM






 Is Excessive Redo Generated during RMAN OPEN Database backup using backup

sets as happens in case of HOT Backup ?

 If NOT , Why ?

 --
 Please see the official ORACLE-L FAQ: http://www.orafaq.net
 --
 Author: VIVEK_SHARMA
   INET: [EMAIL PROTECTED]




-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: 
  INET: [EMAIL PROTECTED]

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Re: RMAN backup - basic Qs

2003-01-16 Thread Maria Aurora VT de la Vega
does this make RMAN hot backups faster or slower than when backing up file in
backup mode?

[EMAIL PROTECTED] wrote:

 To better answer the original question, my understanding of this difference
 is as under:

 Why do you put the tablespace in backup mode during normal hot backups
 without RMAN? This is to avoid backing up split blocks. Say, you have a
 database with a block size of 16K. And that a block is in the process of
 being backed up, with reads happening in chunks of say, 512 bytes.  Assume
 a user transaction updates this block while the backup is in progress. This
 could result in an inconsistent version of the block being backed up, or
 what is called as split blocks.  Putting a tablespace in backup mode, is
 primarily, a flag which tells Oracle to copy the entire block into the redo
 stream, and not just the changed vectors or deltas, which it would have
 done otherwise. This is so that, in case of recovery, the entire block can
 be read from the redo stream, and applied. Hence, this results in an
 increase in the redo size during normal hot backups.

 RMAN however, does not place the tablespaces in hot backup mode.  They use
 the same read consistency mechanism used by the SQL statements. Hence, no
 excessive redo is generated.

 Hope this helps.

 Raj

 Original Message-
 Sent: Thursday, January 16, 2003 1:54 PM
 To: Multiple recipients of list ORACLE-L

 Rman uses the same construct to get the right data in a hot backup as
 sqlplus, the SCN of the database. It reduces excess redo because you don't
 have to put the datafile in backup mode with a begin backup and take it out

 with and end backup.

 HTH,
 Ruth
 - Original Message -
 To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
 Sent: Thursday, January 16, 2003 12:35 PM

 
  Is Excessive Redo Generated during RMAN OPEN Database backup using backup

 sets as happens in case of HOT Backup ?
 
  If NOT , Why ?
 
  --
  Please see the official ORACLE-L FAQ: http://www.orafaq.net
  --
  Author: VIVEK_SHARMA
INET: [EMAIL PROTECTED]

 --
 Please see the official ORACLE-L FAQ: http://www.orafaq.net
 --
 Author:
   INET: [EMAIL PROTECTED]

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--
Maria Aurora VT de la Vega
Oracle DBA
Philippine Stock Exchange, Inc.

If you don't risk anything, you risk even more.


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RE: RMAN backup - basic Qs

2003-01-16 Thread DENNIS WILLIAMS
Maria - Definitely faster. Often hot backups can generate additional redo.

Dennis Williams
DBA, 40%OCP
Lifetouch, Inc.
[EMAIL PROTECTED] 


-Original Message-
Sent: Thursday, January 16, 2003 9:24 PM
To: Multiple recipients of list ORACLE-L


does this make RMAN hot backups faster or slower than when backing up file
in
backup mode?

[EMAIL PROTECTED] wrote:

 To better answer the original question, my understanding of this
difference
 is as under:

 Why do you put the tablespace in backup mode during normal hot backups
 without RMAN? This is to avoid backing up split blocks. Say, you have a
 database with a block size of 16K. And that a block is in the process of
 being backed up, with reads happening in chunks of say, 512 bytes.  Assume
 a user transaction updates this block while the backup is in progress.
This
 could result in an inconsistent version of the block being backed up, or
 what is called as split blocks.  Putting a tablespace in backup mode, is
 primarily, a flag which tells Oracle to copy the entire block into the
redo
 stream, and not just the changed vectors or deltas, which it would have
 done otherwise. This is so that, in case of recovery, the entire block can
 be read from the redo stream, and applied. Hence, this results in an
 increase in the redo size during normal hot backups.

 RMAN however, does not place the tablespaces in hot backup mode.  They use
 the same read consistency mechanism used by the SQL statements. Hence, no
 excessive redo is generated.

 Hope this helps.

 Raj

 Original Message-
 Sent: Thursday, January 16, 2003 1:54 PM
 To: Multiple recipients of list ORACLE-L

 Rman uses the same construct to get the right data in a hot backup as
 sqlplus, the SCN of the database. It reduces excess redo because you don't
 have to put the datafile in backup mode with a begin backup and take it
out

 with and end backup.

 HTH,
 Ruth
 - Original Message -
 To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
 Sent: Thursday, January 16, 2003 12:35 PM

 
  Is Excessive Redo Generated during RMAN OPEN Database backup using
backup

 sets as happens in case of HOT Backup ?
 
  If NOT , Why ?
 
  --
  Please see the official ORACLE-L FAQ: http://www.orafaq.net
  --
  Author: VIVEK_SHARMA
INET: [EMAIL PROTECTED]

 --
 Please see the official ORACLE-L FAQ: http://www.orafaq.net
 --
 Author:
   INET: [EMAIL PROTECTED]

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 San Diego, California-- Mailing list and web hosting services
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 To REMOVE yourself from this mailing list, send an E-Mail message
 to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
 the message BODY, include a line containing: UNSUB ORACLE-L
 (or the name of mailing list you want to be removed from).  You may
 also send the HELP command for other information (like subscribing).

--
Maria Aurora VT de la Vega
Oracle DBA
Philippine Stock Exchange, Inc.

If you don't risk anything, you risk even more.


-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Maria Aurora VT de la Vega
  INET: [EMAIL PROTECTED]

Fat City Network Services-- 858-538-5051 http://www.fatcity.com
San Diego, California-- Mailing list and web hosting services
-
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).
-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: DENNIS WILLIAMS
  INET: [EMAIL PROTECTED]

Fat City Network Services-- 858-538-5051 http://www.fatcity.com
San Diego, California-- Mailing list and web hosting services
-
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).