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Re: Backup Recovery - Cold Backup in Archive log mode

From: Howard J. Rogers <>
Date: Wed, 9 Jun 2004 18:04:27 +1000
Message-ID: <40c6c475$0$31675$>

"Don" <> wrote in message
> Howard,
> We have a database with some tablespaces are for read-only
> applications. Does this mean that I can only backup the datafiles
> related to tablespaces that are being updated? What about system
> related tablespaces? Thanks ..

The short answer to your first question is 'No'. You can backup read-only tablespaces by simply copying the data files associated with them. But a read-write tablespace needs to be placed into hot backup mode before its data files can be copied. Hence: alter tablespace SYSTEM begin backup; ----copy system01.dbf system01.bkp---- alter tablespace SYSTEM end backup;
And having done one tablespace, you can move on to the next until all of them are 'processed'. But as I say, a genuinely read-only tablespace (one for which you have actually said alter tablespace X read only, and not just one which doesn't get much update activity) can have its data files simply copied.

So all data files get copied (and must be, if you want to do point in time recoveries). Only some will need the begin-end backup treatment, and some won't. And system-related tablespaces are treated just like any other read-write tablespace. The only exception is TEMP, because in the event of that getting damaged, you simply drop it and re-create it from scratch.

I think you need to do a bit of background research... Have a look at the backup and recovery documentation. I think you might also want to investigate RMAN, because that will at least make sure you back things up correctly, be it read-only, read-write, system-related or anything else. But even RMAN doesn't you can get away with not understanding what it is you're doing.

Drop me a line at my email address, and I may have something for you that will help fill in some evident gaps.

HJR Received on Wed Jun 09 2004 - 03:04:27 CDT

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