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RAW Device Backup

Occasional Contributor

RAW Device Backup

We are having RAW Device installtion of ORACLE 8.0.4. data files. We are using DD for cold backup of datafiles.

Is it ok to take DD of RAW device into a mounted files system with sepcified name ?

Example :

dd if=/dev/vg03/pro1.data1.dbf of=/oracle/cold/data1.dbf

If so, what about restoration ? Is the following method is ok ?
dd if=/oracle/cold/data1.dbf of=/dev/vg03/pro1.data1.dbf

2. Can we take TAR backup of all files created by the above DD comands in mounted file system, i.e.,

tar -cv /pro1backup/cold/*

Will it work properly. Is anyone using the said method ?


With Rgds
Andy Monks
Honored Contributor

Re: RAW Device Backup

dd is fine. I would recommend, using the 'bs' option. Maybe 'bs=64k' or higher. It should speed things up.

You might want to look at something like HP's Omniback. It can backup filesystems and raw devices to the same tape etc. It's a very good tools for such things. That way, you won't have to dd the raw data to filesystems and then back it up.
Andreas Voss
Honored Contributor

Re: RAW Device Backup


sounds to me a little bit strange.
If you have a raw device ie. /dev/vg01/lvol1
then you don't have any files on it - raw devices are used in full capacity without any filesystem structure.
So dd would be the best to backup but with the raw device file ie:
dd if=/dev/vg01/rlovol1 of= bs=64k
If you have a filesystem on it and mounted dd is not a good choice. A tar backup is the better thing but remember to shut down your oracle application before backup.
Of course when you stop oracle and umount the filesystem you could do a dd but i think this is not a good idea.


Occasional Contributor

Re: RAW Device Backup

Thanks for every One.

This worked!!!!,

We created dummy tablespace with a raw
datafile & we took the dd backup on
mounted file system,& tar backup of the
same taken.

Then we removed the raw filesystem & recreated,from the tape the dd file restored
back to the mounted directory,& through
dd copied back as the original raw datafile.

Database came up with out any table loss.

Thanks & Regards