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Roll forward from a hot backup [message #334486]

Wed, 16 July 2008 18:12

rleishman
Messages: 3728
Registered: October 2005
Location: Melbourne, Australia

Senior Member

We're specifying database application requirements for a client who is outsourcing the build of the machines and DB to another provider.

Our requirement - as specified by the client - is for 24x7 availability of the database. ie. Backups against a live database. We also want the ability to roll-forward to a point in time.

The other provider is telling us that you can stay online during backup (hot backup) but cannot easily/safely/reliably roll forward during a restore. ie. It's technically possible, but you wouldn't want your entire strategy hinged on it.

They are pitching for a cold (offline) backup on a weekly basis with daily incrementals.

I'm having trouble believing that Oracle does not have a rock-solid high-availability backup and recovery solution.

Looking at the Oracle Backup and Recovery Guide, I see no warnings about hot (online) backups. It describes rolling forward as a statement of fact without caveats.

What's the recommended approach to high availability backup and recovery?

Ross Leishman

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Re: Roll forward from a hot backup [message #334487 is a reply to message #334486]

Wed, 16 July 2008 18:19

BlackSwan
Messages: 26766
Registered: January 2009
Location: SoCal

Senior Member

>What's the recommended approach to high availability backup and recovery?

RMAN - hot backups are 100% solid & reliable as long as DB is in archive redo logs enabled mode.

V11 RMAN has capability to clone any live, online DB.

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Re: Roll forward from a hot backup [message #334492 is a reply to message #334486]

Wed, 16 July 2008 19:54

Mahesh Rajendran
Messages: 10708
Registered: March 2002
Location: oracleDocoVille

Senior Member
Account Moderator

I second that.
Long back (2002,Oracle 9i/RAC) we demonstrated RMAN TSPITR to recover databases to the minute and even to a point-in-time between 5 seconds.
It was a duplication process so we had to rely on backups already created (datafiles + archivedlogs).
Restoration should be of the same process, only applying information from ***available*** redolog files.
With 10g and above, there are many nice features like image copies,incrementally updated backups that might help more.
Actual options may for high availability depends environment.
Using ASM for databases with external redundancy, multiple archivedlog backups, properly making use of FRA etc.
>>They are pitching for a cold (offline) backup on a weekly basis with daily incrementals.
Well, I myself live with same paranoia and backup the database in very possible method I can afford to.

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Re: Roll forward from a hot backup [message #334498 is a reply to message #334486]

Wed, 16 July 2008 20:40

ebrian
Messages: 2794
Registered: April 2006

Senior Member

rleishman wrote on Wed, 16 July 2008 19:12

The other provider is telling us that you can stay online during backup (hot backup) but cannot easily/safely/reliably roll forward during a restore. ie. It's technically possible, but you wouldn't want your entire strategy hinged on it.

I would be quite apprehensive of putting my B&R strategy into the hands of a provider if they were telling me this.

rleishman wrote on Wed, 16 July 2008 19:12

Our requirement - as specified by the client - is for 24x7 availability of the database....

They are pitching for a cold (offline) backup on a weekly basis with daily incrementals.

24x7 availability and cold backup are diametrically opposed.

As the others have indicated, Oracle has absolutely NO problem whether the backup is a cold backup or hot backup. An additional detail that should be taken into consideration is use of flashback features. Flashback database can provide an alternative to conventional PITR and is typically more efficient and seamless to perform.

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Re: Roll forward from a hot backup [message #334507 is a reply to message #334498]

Wed, 16 July 2008 21:38

rleishman
Messages: 3728
Registered: October 2005
Location: Melbourne, Australia

Senior Member

Thanks everyone.

That all aligns with my experience. I figured I was being fed a line, but had to check.

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