Re: I/O activity during HOT backups

From: <dmeng_at_focal.com>
Date: Mon, 19 Jun 2000 14:08:11 -0500
Message-Id: <10533.109755@fatcity.com>

That is incorrect. During hot backups, datafile themselves are up-to-date: changes are written to them
as usual. It is the FILE HEADER that get frozen. That is why if your database crashes during a hot backup,
all you have to do is taking your tablespace out of hot backup mode -- which will update the file headers. (
this applies to 7.3 and later versions).

HTH Dennis Meng
Database Administrator
Focal Communications
847-954-8328

                                                                                       
                    Lisa_Koivu_at_ge                                                      
                    lco.com              To:     Multiple recipients of list ORACLE-L  
                    Sent by:             <ORACLE-L_at_fatcity.com>                        
                    root_at_fatcity.        cc:                                           
                    com                  Subject:     Re: I/O activity during HOT      
                                         backups                                       
                                                                                       
                    06/19/00                                                           
                    02:50 PM                                                           
                    Please                                                             
                    respond to                                                         
                    ORACLE-L

No! The command below stops all writes to the datafiles in the tablespace for
the duration of the backup, to ensure consistency.

The i/o overload I see during backups is the data being copied out to our backup
server. And it is usually very high: like 80% of all current activity.

Lisa

Dan.Hubler_at_midata.com on 06/19/2000 01:18:14 PM

Please respond to ORACLE-L_at_fatcity.com

To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> cc: (bcc: Lisa Koivu/GELCO)

Please settle a discussion amongst our DBA team:

Is there ANY I/O that takes place to the database files (*.DBF) during a HOT backup? (That is, ALTER TABLESPACE BEGIN BACKUP).

If not, how does the process work?

Thanks.

???

--
Author:
  INET: Dan.Hubler_at_midata.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (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).






--
Author:
  INET: Lisa_Koivu_at_gelco.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (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

Received on Mon Jun 19 2000 - 14:08:11 CDT