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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Oracle DB Backups on SAN with ALTER SYSTEM SUSPEND

RE: Oracle DB Backups on SAN with ALTER SYSTEM SUSPEND

From: Jeremiah Wilton <jwilton_at_speakeasy.net>
Date: Wed, 26 Mar 2003 16:23:47 -0800
Message-ID: <F001.00573E14.20030326162347@fatcity.com> 





Michael,



Your split is no different from a very fast hot backup.  So, it does
not matter that the split is not atomic.  Just use hot backup mode,
and generate a binary controlfile using backup controlfile to 'file'
and copy it to your destination.  A the destination just recover the
one or two logs generated while you did the split.  Forget about
suspend, it serves no purpose and is just decreasing your system's
availability.  BTW, your current hot-live copies of controlfiles are
potentially invalid and totally unsupported.



All that expensive equipment and you're suspending!  Don't take the
thing out of service unnecessarily!


--
Jeremiah Wilton
http://www.speakeasy.net/~jwilton

On Wed, 26 Mar 2003, Hand, Michael T wrote:



> Jeremiah,

> The only reason I could forsee is if the split is not atomic.  This is the

> case

> in our (Non-SAN) environment.  The split takes several minutes and the

> control

> files have been mis-matched when the DB copy was started on the reporting

> server.

> My solution under V8.0 was to use only one of the control files for

> reporting

> database.

> 

> My $0.02

> Mike Hand

> 

> -----Original Message-----

> Sent: Wednesday, March 26, 2003 11:04 AM

> To: Multiple recipients of list ORACLE-L

> 

> 

> Why do you have to suspend?

> 

> --

> Jeremiah Wilton

> http://www.speakeasy.net/~jwilton

> 

> On Wed, 26 Mar 2003, Hemant K Chitale wrote:

> 

> > 

> > We want true server-less backups.  I know that RMAN's overhead is [much]

> lower

> > than that of the ALTER TABLESPACE BEGIN/END BACKUP but the

> > Snapshot method in a SAN [akin to splitting and resilivering a mirror, in 

> > some ways]

> > should be much faster.  The database is in BACKUP mode only for the time

> it

> > takes the SAN to create the Snapshot which, I've been told, is seconds or 

> > minutes,

> > irrespective of the size of the database.  [Of course, there will be some 

> > time lag

> > between the first ALTER TABLESPACE <tbs> BEGIN BACKUP and the

> > ALTER SYSTEM SUSPEND command when the database will be doing a

> > Checkpoint at each Tablespace, and writing more Redo for transactions upto

> > the ALTER SYSTEM SUSPEND and will the END BACKUPs are still being issued.]

> > 

> > And I cannot use RMAN with the Snapshot method.  I must SUSPEND the

> database

> > and RMAN does not support that.

> > 

> > See 

> >

> http://download-west.oracle.com/docs/cd/A87860_01/doc/server.817/a76993/osba

> ckup.htm#4233

> > "Making Backups in Suspend Mode"  in Chapter 4 "Performing Operating

> System 

> > Backups"

> > of the 8i Backup and Recovery Guide.

> > 

> > Hemant

> > 

> > At 05:38 AM 26-03-03 -0800, you wrote:

> > >Hemant - If you've got to rework your backup script anyway (and retest

> it),

> > >why not consider switching to RMAN at this time? In my experience,

> > >negligible interference with production during a hot backup.

> > >

> > >Dennis Williams

> > >DBA, 40%OCP, 100% DBA

> > >Lifetouch, Inc.

> > >dwilliams_at_lifetouch.com

> > >

> > >

> > >-----Original Message-----

> > >Sent: Tuesday, March 25, 2003 10:49 PM

> > >To: Multiple recipients of list ORACLE-L

> > >

> > >

> > >

> > >Some of my databases will be migrating to a SAN.

> > >Currently, I run hot backups to disk using the

> > >ALTER TABLESPACE <tbs> BEGIN BACKUP ;

> > >host cp <file> <target>;

> > >ALTER TABLESPACE <tbs> END BACKUP

> > >

> > >On a SAN, where the vendor promises server-less backups

> > >using Snapshots, I guess I would have to issue the

> > >commands :

> > >ALTER TABLESPACE <tbs1> BEGIN BACKUP

> > >..

> > >..

> > >ALTER TABLESPACE <tbsN> BEGIN BACKUP

> > >

> > >ALTER SYSTEM SUSPEND

> > >....> take a "snapshot"

> > >ALTER SYSTEM RESUME

> > >

> > >ALTER TABLESPACE <tbs1> END BACKUP

> > >..

> > >..

> > >ALTER TABLESPACE <tbsN> END BACKUP

> > >

> > >

> > >Would that be right ?  What are real-world experiences

> > >[bugs / time required for the SUSPEND/RESUME, actually

> > >flushing all I/O to the disks] ?

> > >

> > >The SAN will be a Hitachi 9970 sold by Sun.

> > >The databases will be 8.1.7 32-bit / 64-bit on Solaris 8.

> > >

> > >Hemant K Chitale

> > >http://hkchital.tripod.com

> > >--

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

> > >--

> > >Author: Hemant K Chitale

> > >   INET: hkchital_at_singnet.com.sg

> > >

> > >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

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> > >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: DWILLIAMS_at_LIFETOUCH.COM

> > >

> > >Fat City Network Services    -- 858-538-5051 http://www.fatcity.com

> > >San Diego, California        -- Mailing list and web hosting services

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> > 

> > Hemant K Chitale

> > My personal web site is :  http://hkchital.tripod.com

> > 

> > 

> > -- 

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

> > -- 

> > Author: Hemant K Chitale

> >   INET: hkchital_at_singnet.com.sg

> > 

> > Fat City Network Services    -- 858-538-5051 http://www.fatcity.com

> > San Diego, California        -- Mailing list and web hosting services

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> > 

> > 

> 

> -- 

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

> -- 

> Author: Jeremiah Wilton

>   INET: jwilton_at_speakeasy.net

> 

> 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: 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).

> -- 

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

> -- 

> Author: Hand, Michael T

>   INET: HANDM_at_polaroid.com

> 

> 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

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> also send the HELP command for other information (like subscribing).

> 

> 


-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Jeremiah Wilton
  INET: jwilton_at_speakeasy.net

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
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Received on Wed Mar 26 2003 - 18:23:47 CST












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