Re: ORACLE Hot Backups and Recovery

"G.K.Subramanian" <gks_at_mailbag.com> wrote:

>As a result of this, the restore process takes a very long time.
>The tape device has to rewind everytime, since it uses a
>separate 'cpio' command for each file that is backed up.
>This is against the process where you would have all the
>files in a single directory and back it up.

>Is there a better way of doing this ?. Is this the limitation
>of the backup process. I have the same problem while restoring
>the ORACLE files using OMNIBACK.
 

>I appreciate any leads to resolve the problem.
 

>Config : HP 9000 / 10.01 /ORACLE 7.X

I don't know how OMNIBACK works, but you presumably have to supply a unix device file name for your tape device to it, eg /dev/rmt/0m ??

If so, all you need to do is specify a "no rewind" device file for that tape - the convention is that a "no rewind" device file has an "n" in the name, eg /dev/rmt/0mn. This will mean that each cpio command writes immediatly, rather than having to search for the EOT marker, write the file, and then rewind :)

So, if using tar, like I do, this:

	tar cvf /dev/rmt/0mn <file>
	tar cvf /dev/rmt/0mn <another file>

would write <file> to tape, followed by <another file>, *without rewinding*.

When I first implemented this, I reduced our hot backup time from 10 hours to 55 minutes :>

--
Simon Holt --  System Designer/DBA
** My opinions are not nescessarily those of my employers **
Britannia Zinc Ltd.  (+44) 0117 982 3646