Re: incremental backups
- From: "Jared Still" <jkstill@xxxxxxxxx>
- To: ryan_gaffuri@xxxxxxxxxxx
- Date: Fri, 2 Mar 2007 13:28:45 -0800
On 3/2/07, ryan_gaffuri@xxxxxxxxxxx <ryan_gaffuri@xxxxxxxxxxx> wrote:
I spoke to someone I know who has been a dba for 20 years. He is opposed
to using incremental backups. This is his rationale. He says that it takes
longer to apply incremental backups, plus its one more file that can be
corrupted.
Takes longer than what to apply?
Archive logs?
Here's a thought experiment:
Make a level 0 backup;
Delete and insert 1m rows in a table a few times.
Do a level 1 backup.
Backup the archive logs.
Now restore the database.
Do you think RMAN would rather apply a level 1 incremental backup that
might be a few megabytes?
Or a couple hundred gig of archive logs?
RMAN automatically uses a level 1+ backup when available and appropriate.
Archive logs will be involved in the restore, but the level 1 backup
will make it unnecessary to restore many of the archive logs.
however, I would assume most larger systems cannot take a full backup as
often as you can take an incremental backup so you have to apply more redo.
Is this a better option than applying incremental backupsets?
Level 1 will not likely reduce backup time. It will reduce the amount of
redo that needs to be applied to the database.
It will also reduce the amount of storage media needed for backups.
It can also reduce restore times.
--
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
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