RE: diff between incremental and archive backups
Date: Mon, 23 Nov 2015 02:56:25 -0500
Message-ID: <03ab01d125c4$741efa60$5c5cef20$_at_rsiz.com>
Again, well put, a good omission to mention, and in accordance with “Never trust your career to a single piece of spinning rust or ribbon rust.” Thanks!
As for the path about quick business continuation of very massive sets, meeting such a requirement with backups rather than switch-over targets of some sort implicitly requires that the full backup itself, any incrementals, and at least one copy of the archived redo logs is on fast media that in the case of the full backup can merely be pointed to in place of the primary files as opposed to being copied at all. I also recommend that the online logs and last good control file be preserved somewhere fast as the first step of recovery, preserving your ability to try again should they be modified during a recovery that fails for any reason.
mwf
From: kathryn axelrod [mailto:kat.axe_at_gmail.com]
Sent: Sunday, November 22, 2015 8:30 PM
To: mwf_at_rsiz.com
Cc: sbecker6925_at_gmail.com; Brian.Zelli_at_roswellpark.org; oracle-l
Subject: diff between incremental and archive backups
There seem two paths on the topic.
Replying to the first one, I didn't see this mentioned, so apologize if it was: i'd add the warning that, if the plan has only one copy of the logs backed up and you lose just one of those many logs, you may lose a Lot of data. e.g. you do a full on Sunday, Jan 1..lose one log on Monday, Jan 2 due to corruption or other..and you decide you want to do a pitr on Saturday, January 7..you can't. You'll be forced to go all the way back to right before the missing log.
On Friday, November 13, 2015, Mark W. Farnham <mwf_at_rsiz.com <javascript:_e(%7B%7D,'cvml','mwf_at_rsiz.com');> > wrote:
Well put.
Consider also that if a given block is modified many times, then the size of the deltas in the redo stream likely exceeds the size of the one current version of the block that will need to be written to the incremental backup and applied in the course of rolling forward from the full backup through any incrementals.
Having the two possible recovery scenarios might allow you to minimize the recovery time depending on the texture of updates to your database.
mwf
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Sandra Becker
Sent: Friday, November 13, 2015 2:10 PM
To: Brian.Zelli_at_roswellpark.org
Cc: oracle-l (oracle-l_at_freelists.org)
Subject: Re: diff between incremental and archive backups
Depending on how many archivelogs your database writes in a week, that could be a lot of logs to apply. Consider if you have the space to store them, or time to restore them to disk, and the time to apply all the logs vs. doing incremental backups and applying fewer logs. Just something to consider.
Sandy B.
On Fri, Nov 13, 2015 at 11:59 AM, Zelli, Brian <Brian.Zelli_at_roswellpark.org> wrote:
So we were having a discussion about rman incremental backups. And the question came up that if I do an rman full once a week and then rman back up of the archive logs the rest of the week, that’s all I need to do a point in time restore. I don’t have to do incremental backups. Is this an accurate assumption?
Brian
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Received on Mon Nov 23 2015 - 08:56:25 CET