I have gone through this process. We used to backup to disk using scripts as
described in Velpuri's book. We now use RMAN to backup to disk. Your backups will be
faster and smaller in size, because RMAN will skip unused blocks and it also allows
you to specify mutilple channels. I can backup a 70 Gb database in about 60 to 90
minutes. Here is a sample script:
run
{
allocate channel ch1 type disk format '/bkup9/oracle/%d/full_s%s_p%p_%t';
allocate channel ch2 type disk format '/bkup3/oracle/%d/full_s%s_p%p_%t';
set limit channel ch1 kbytes=1000000; # Limit sets to 1 Gb.
set limit channel ch2 kbytes=1000000;
backup full database
tag='daily_full_backup';
allocate channel ch3 type disk format '/bkup3/oracle/%d/arc_s%s_p%p_%t';
set limit channel ch3 kbytes=1000000;
backup (archivelog until time 'sysdate-1/24' delete input
channel ch3
);
}
I do archivelog backups with a separate command, because RMAN can be a bit touchy when
it comes to archivelogs. If none exist for the time specified, then the backup will
fail. This way my database backup will be successful if there is a problem with the
archivelog backup.
I would skip the incremental stuff. Just do full backups unless you are talking huge
databases.
To tell RMAN what backup files are available on disk, prior to a restore, run this
command:
# Check which backups are available on disk.
allocate channel for maintenance type disk;
crosscheck backup;
release channel;
or this one if you are in noarchivelog mode:
# Check which backups are available on disk.
allocate channel for maintenance type disk;
crosscheck backup of database;
crosscheck backup of controlfile;
release channel;
Jay Hostetter
Oracle DBA
D. & E. Communications
Ephrata, PA USA
>>> [EMAIL PROTECTED] 01/17/02 12:45PM >>>
See currently we are using Unix scripts to do our hot backups .We take the
backup on disk and everynight after the disk backup we copy the backup on
tape using Veritas Net Backup.
Presently we keep 2 days worth of backups on the disk and 3 days of archive
logs.That means at any point in time i have the last 2 days backup on disk
(just for fatster recovery so that we can aviod going to tapes in case of a
failure).
Now if we start using RMAN ,we would be taking hot backups (mostly using
increamental strategy) using RMAN.So for e.g. we start on say sunday taking
an incremental level 0 backup on disk.RMAN only remmbers the disk backup
...right???? Note that we will also be copying the backups on tape but that
will be independent of RMAN since it is not done using RMAN.
Say the next 3 days of the week ,we do increamental level 1 backups .On the
3 rd day (i.e. Wednesday) i would have only Monday's and Tuesdays' backup
on disk (which are the inceemental llevel 1 backups since the whole ideas is
to keep last 2 days backup om disk).
So if we have a failure on Wednesday then RMAN would look for the
incremental level 0 backup of Sunday on the disk but that backup is not
present on the disk now.
I hope i have cleared it up enough.
Now my question is can we maintain the same policy of keeping 2 days backup
on disk by using RMAN.
What kind of backup strategies do RMAN users follow? Are RMAN backups
usually taken on tape directly ? Is it faster to take backups on tape rather
on disk while using RMAN?
Could RMAN users share their backup/recovery strategies ,please.
TIA
----- Original Message -----
To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
Sent: Thursday, January 17, 2002 5:55 AM
> If you are using a recovery catalog then rman keeps track of everything
> there. He knows if you've been naughty, he know if you've been nice, he
> knows....OOOPS I got carried away. But when you do a restore using rman
he
> will tell you what backup sets you will need.
>
> Ruth
> ----- Original Message -----
> To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
> Sent: Wednesday, January 16, 2002 6:20 PM
>
>
> Hi
> Currently we are using Unix scripts to do backups.We keep last 2 days of
> backups on the disk and also take the backups on tape daily.
> We are planning to use RMAN for backups and would like to maintain the the
> same policy of 2 days backup on disk and daily tape backups.
> Is it possible to implement this using RMAN? Which backup will RMAN
remember
> (while restore) the disk backup or the tape backup?
> If we try to use the incremental strategy ,then how would RMAN remember
the
> last incremental level 0 backup ? It will not be present on disk since we
> only keep the last 2 days backup on it.
> How do i use RMAN to do restore/recovery in this case?
>
>
> I heard that taking backups on tape is faster than on disk when using
RMAN?
> Is it true?
>
> Could RMAN users share their backup/recovery strategies ,please.
>
> TIA
>
>
>
>
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Ruth Gramolini
> INET: [EMAIL PROTECTED]
>
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
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