Re: database could not be started

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.

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 Sun Aug 10 2003 - 04:20:53 CDT