backup question

[leonard905]

Hi all,

If I take and full export of my db (logical backup) and also copy all the control files, data files and redo log files (physical), which one of the two methods saves me storage space. And why?

Thanks,

[gopi]

Export

Export is compressed

A cold backup of all the dB files is the size of the sum of all the files

[yoda]

Export/import is not a backup methodology
marist89 - http://www.dbasupport.com/forums/sho...6&pagenumber=3

[leonard905]

I know that export is not a backup method. I just need a figures to justify the need for both physical and logical methods for our production db.

[stecal]

Do you mean copy the redo log files as in a cold backup? Why copy those files? I think every book (well, quite a few of the more authoratative ones anyway) explicity tell you NOT to copy the redo log files in a cold backup. That should save you some space.

[SANJAY_G]

Originally posted by stecal:
Do you mean copy the redo log files as in a cold backup? Why copy those files? I think every book (well, quite a few of the more authoratative ones anyway) explicity tell you NOT to copy the redo log files in a cold backup. That should save you some space.

In fact, you should copy online redo logs files with cold backup.

Sanjay

[jmodic]

Originally posted by SANJAY_G

In fact, you should copy online redo logs files with cold backup.

In fact, the only case when you need to copy online redo log files with cold backup is when your databas was shut down in ABORT mode prior to backup.

[SANJAY_G]

Originally posted by jmodic
In fact, the only case when you need to copy online redo log files with cold backup is when your databas was shut down in ABORT mode prior to backup.

Well, what happens if you lose everything (including redo logs) and have to recover from a cold backup?
The only option you have is, restore datafiles, cotrolfile and open the database with RESETLOGS and you may also have to issue a fake recover command in order to avaoid ORA-01139

And when you open db with RESETLOGS all your previous hot backups will be invalidated.

I would still backup redo logs with cold backup to avoid going through all these hassles.

Sanjay

[jmodic]

If you loose everything and have to restore from cold backup (BTW, why would you *have to* restore from cold backup, you could recover from hot backup as well), why would your previous hot backups be invalidated? They are still perfectly valid, no matter if you had to open your database with RESETLOGS. You still can recover to any point in time, both prior to resetlogs (in which case your starting backup would be any hot backup taken prior to RESETLOGS) and after it (in which case you would use any backup taken after the RESETLOGS).

[Edited by jmodic on 10-04-2002 at 05:13 AM]

[pando]

Originally posted by SANJAY_G

Originally posted by stecal:
Do you mean copy the redo log files as in a cold backup? Why copy those files? I think every book (well, quite a few of the more authoratative ones anyway) explicity tell you NOT to copy the redo log files in a cold backup. That should save you some space.

In fact, you should copy online redo logs files with cold backup.

Sanjay

Sanjay I guess you have not used RMAN for cold backups. RMAN does not backup online redo logs whatsoever, not in cold backups or hot backups.