Re: Backups on raw devices

On Jun 15, 2001 at 04:05:49PM, Christopher Spence wrote:
> >In Oracle, you will get an "inconsistent"
> >image of the data file, but that is true
> >with any "manual" hot backup - cpio, tar,
> >cp, etc. It is not a problem - iff the
> >tablespace(s) are in backup mode.
> >(Wasn't there something about this on the OCP exam?)
>
> This is exactly the reason why Oracle will write full blocks to the redo
> logs during tablespace backup mode. Yes, the block is inconsistent, but if

It's done if a block appears in the buffer cache -- the full image of a block is written. If the block remains in the buffer cache for a long period of time the regular logging will be done. If it's flushed and loaded again (and the tablespace still in hot backup mode) -- the full image block will be logged again. It's not a logical approach but it's done like that. RMAN can be used to eliminate such a behavior for some heavy loaded systems.

-- 
Vladimir Begun               | The more things change, the more they'll
http://vbegun.net/           | never be the same again.
http://vbegun.net/wap/       | 
me_at_vbegun.net                | 
-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Vladimir Begun
  INET: jester_at_whale.sunbay.crimea.ua

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).