Re: Cluster Data On Tap (CDOT)

From: Mladen Gogala <>
Date: Tue, 5 Dec 2017 19:17:05 -0500
Message-ID: <>

On 12/04/2017 07:44 PM, Gus Spier wrote:
> I am studying up on CDOT, which appears to me to be NetApp's answer to
> virtualization. While I work through the documentation, I am
> ensorcelled by the concept of database recovery by means of snapshots.
> I have never had the opportunity to try to restore/recover a database
> with a snapshot. To me, it sounds like the efforts of a system
> administrator who tried to restore and recover a production database
> with operating system copies of the open data files. Of course, that
> didn't work and much hilarity and mayhem ensured.
> I'm sure that people smarter than me have figured out how to use
> snapshots to recover databases, but I've never been able to reason my
> way through the process. Does anybody know how it is accomplished?
> Fond regards,
> Gus

Yes, I do know how that works. Snapshots are standard DB tool for backup and virtualization.  Before snapping the LUNs, the database is put into the backup mode, to ensure that there is no hilarity and mayhem. This is achieved by an ancient Oracle command, well known from the EBU times: "ALTER DATABASE BEGIN BACKUP". Log files are backed up using RMAN. Now, when you get a LUN snapshot, you recover it by applying the logs, from RMAN. I've done it many times. Commvault can automate that for you with many other arrays, not just NetApp. BTW, NetApp is a rock solid array and I've had very little trouble with it during the course of my career.

Mladen Gogala
Oracle DBA

Received on Wed Dec 06 2017 - 01:17:05 CET

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