Re: re BCV / SnapShot / SnapClone and the ALTER SYSTEM

Yes, I hadn't read the line
"so the tablespaces had to be put into backup mode or (8i and after) the database had to be suspended"
you _do_ have an OR between the backup mode and the database .. suspended.

We hadn't heard of anyone using the SUSPEND and didn't want to take the chance of a database "seeming to be frozen" for a few seconds or upto a minute {weren't sure
how long the split would actually take to run before we implemented it}. We'll stick to putting the tablespaces in BACKUP mode.

Hemant

At 09:34 PM 09-01-04 -0800, you wrote:
>I should have expressed myself more clearly. Suspend is not necessary,
>it's only fast. Basically,
>with suspend, you don't put tablespaces into backup mode. You suspend,
>resync, split
>and start aonther instance as if it crashed. As no I/O is going to disk,
>datafiles aren't
>fuzzy, so no recovery is needed. Problem with this approach is that the
>original instance
>is not usable during this time. All sessions are hanging. Benefit is that
>no recovery is
>needed and if everything goes OK, you're done very, very quickly. It's
>either-or approach,
>not a combination.
>
>
>On 2004.01.10 00:09, Hemant K Chitale wrote:
> >
> > Mladen,
> > Is the "ALTER SYSTEM SUSPEND" really necessary.
> >
> > We've just implemented SnapClone mechanims for three Oracle DBs on
> > Hitachi and EMC SANs, We've been told that only ALTER TABLESPACE ...
> BEGIN
> > BACKUP
> > is necessary.
> > What we do is
> > 1. Issue an ALTER TABLESPACE ... BEGIN BACKUP for all the tablespaces
> > 2. "split" the image for the /oradata? filesystems
> > 3. Issue an ALTER SYSTEM ARCHIVELOG CURRENT {and also ALTER DATABASE
> > BACKUP CONTROLFILE TO ..}
> > 4. "split" the image for the /archlogs filesystem {for the archivelogs
> and
> > the controlfile backup}
> > 5. Backup the split /oradata? and /archlogs filesystems
> > 6. ReSynch
> >
> >
> > At 07:24 PM 09-01-04 -0800, you wrote:
> > >Let me explain, because I have a little bit of experience with it.
> > >a) BCV's are replicated disks which are synchronized using TimeFinder.
> > > and then separated from the source. The phrase "splitting BCV's"
> means
> > > producing an exact disk copy of the original disks, similarly to
> what
> > > dd can
> > > do. It's an ideal way to make a copy of an instance. Last time I
> > > checked,
> > > BCV's weren't supported by RMAN (it may have changed now), so the
> > > tablespaces had to be put into backup mode or (8i and after) the
> database
> > > had to be suspended (very litle known trick is "ALTER SYSTEM
> SUSPEND",
> > > which abruptly ceases all the I/O in the database, without shutting
> > > it down).
> > >b) RMAN is an oracle tool which works in conjunction with Legato (EMC),
> > >NetBackup(Veritas),
> > > Tivoli, Alexandria or SyncSort backups. RMAN doesn't know how to
> > > write to tape and needs
> > > a 3rd party backup to do so. The part that Veritas, Legato or IBM
> > > will charge you for is
> > > called libobk.so and is an interface which enables RMAN to work
> with
> > > their particular tool.
> > > RMAN is a very good tool which can do many things in a very easy
> way
> > > and without
> > > generating a TB of redo archives for the duration of hot backup
> mode.
> > > Robert Freeman's
> > > book is definitely the best source for anything RMAN around.
> > >
> >
> > Hemant K Chitale
> > Oracle 9i Database Administrator Certified Professional
> > http://hkchital.tripod.com {last updated 05-Jan-04}
> >
> >
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > --
> > Author: Hemant K Chitale
> > INET: hkchital_at_singnet.com.sg
> >
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>
>--
>Mladen Gogala
>Oracle DBA
>--
>Please see the official ORACLE-L FAQ: http://www.orafaq.net
>--
>Author: Mladen Gogala
> INET: mgogala_at_adelphia.net
>
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Hemant K Chitale
Oracle 9i Database Administrator Certified Professional http://hkchital.tripod.com {last updated 05-Jan-04}

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Hemant K Chitale
  INET: hkchital_at_singnet.com.sg

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