--
"Anton Buijs" <remove_aammbuijs_at_xs4all.nl> wrote in message
news:3f360e76$0$49105$e4fe514c_at_news.xs4all.nl...
> As quarkman says: don't talk about cold or hot backup but about
noarchivelogmode
> versus archivelogmode.
> A cold backup (alias offline backup) is made with a closed database; the
db can
> run noarchivelog or archivelogmode, not relevant.
> A hot backup (alias online backup) is made with of an open database; it
requires
> the db to run in archivelogmode and the tablespace be put in backup mode
while
> its files are copied to the backup.
> Remark the subtle difference: a cold backup of an archivelogmode database
is
> possible.
> From a noarchivelogmode database only a cold backup can be taken and it
must
> include all files (database files, at least one controlfile, redos: that's
the
> discussion) to be able to do a restore.
>
> I agree with most of your post when I read "noarchivelomode" instead of
"cold
> backup" and "archivelogmode" instead of "hot backup". See comments.
Ok. But, until someone tells me it will not work, when I do cold backups of
my archivelogmode database, I will backup REDO logs and use them for a
restore if ever needed . Of course, the hot backups are the primary restore
backup and they do not include REDO logs. The colds backups are just backups
to the hot backups. Of course, I also take nightly full export backups too
which of course are a last resort for a full database recover.
I don't mind being called paranoid :)
Seems more likely that my archivelogmode database that is cold backup'ed up
with REDO logs will likely contain the REDO logs (or then none of the files
will be there).
As opposed, to relying on the iffy "clean shutdown". Too many things have
happended to me before to make the "clean shutdown" not clean and I suspect
other scenarios where this could still happen.
>
> Burton Peltier <burttemp1REMOVE_THIS_at_bellsouth.net> schreef in
berichtnieuws
> Q9mZa.10304$AO3.4778_at_fe02.atl2.webusenet.com...
> | "quarkman" <quarkman_at_myrealbox.com> wrote in message
> | news:oprtoew3bhzkogxn_at_haydn...
> | > Sorry about the formatting of this one... God knows what is going on!
> | > ------------
> |
> | lol... good point :) ... see <biggggg snip> below.
> |
> | Your method (never backup REDO logs) will probably save some poor newbie
DBA
> | from making a big mistake - restoring REDO logs when recovering from a
hot
> | backup. I appreciate the perspective.
>
> Exactly the point of Quarkman.
> But under the condition you do a clean shutdown (so having the discipline
to do
> startup restrict/shutdown immediate in the case of a shutdown abort before
a
> backup begins).
>
> | I suppose I am thinking more about day to day support and monitoring of
> | backups not getting done properly and someone missing the fact that
> | "something" started happening sometimes that is preventing a clean
shutdown.
> | Without the REDO logs in the cold backup, you have potential problems.
> |
> | Another way that (to me) seems consistent (for a newbie DBA too) and
> | possibly? less prone to mistakes:
> |
> | - Always backup and restore REDO logs for cold backups.
> | - Never backup or restore REDO logs for hot backups.
>
> If that's your preference, ok, but only when you read it as:
> Always backup and restore redologs for a *noarchivelogmode* database
> Never backup redologs for a *archivelogmode* database.
>
> But in the vision of Quarkman (and I support it):
> Never backup redologs and always do a clean shutdown.
> Because that's the most easiest rule to remember. Only the experienced DBA
(and
> that is the minority) can deal with the subtle details.
>
> | Then again, I suppose an important point is also needed - never put cold
> | backups in the same "place" (directory or whatever) as hot backups.
> |
> | What's more likely ?
> | 1) DBA restoring a REDO log from a cold backup while also restoring
> | datafiles from a hot backup?
> Don't talk about cold/hot but [no]archivelogmode and this question
disappears.
>
> | 2) DBA restoring from a cold backup that happens to have not had a clean
> | shutdown?
> Could not happen with properly implemented backup solutions that followed
the
> simple principle of Quarkman (don't backup redos, always shutdown clean).
>
> | As always, it depends :)
> Ofcourse. but good and simple "best practices" can make live easier for
the less
> experienced.
>
>
Received on Mon Aug 11 2003 - 00:42:17 CDT
