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DB backup/restore on mirrored disks

DB backup/restore on mirrored disks

We have Oracle8i on HPUX11.0 mirrored disks.
What is the procedure for backing/restoring DB without stoping instances (taking from mirror one disk and then returning it back)?

Patrick Wallek
Honored Contributor

Re: DB backup/restore on mirrored disks

You are not going to be able to take an online backup of a database by just splitting off the mirrors. You need to look into Oracle hot backups. There are a number of steps that need to be taken within the DB itself before you even get to the point of thinking about splitting mirrors, etc.
Justo Exposito
Esteemed Contributor

Re: DB backup/restore on mirrored disks

Hi Arturas,

I Think that the only way to do is with the online JFS from Veritas, if you have it you can do it an snapshot of your file systems.

The other way is the Oracle online backup using RMAN.

Hope this helps,

Help is a Beatiful word
Jim Turner
HPE Blogger

Re: DB backup/restore on mirrored disks

Hi Arturas,

What I think you are trying to achieve is what is commonly done with Business Copy Volumes (BCV) on arrays.

1. Drop the database.
2. Split-off the BCVs.
3. Start the database.
4. Mount the BCVs on alternate mountpoints.
5. Backup the data therein.
6. Unmount the BCVs.
7. Merge the BCVs back in.

I think this is somewhat achievable by splitting off mirror copies, but someone else who has actually done it will have to give you detailed guidance.

If you want zero downtime, then you will need a solution like Pat has prescribed whereby you have Oracle Recovery Manager (RMAN) integrated with a backup product like Omniback.


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Honored Contributor

Re: DB backup/restore on mirrored disks


you can do what patrick suggested. Take a hot backup of the oracle database. For this put the database in hotbakup mode, take the backup and take the database out from hotbackup mode. There is no downtime, but the datbase access will be a little slow. So don't do it during peak hours. you can talk to your DBA to explore this. Also if you want you can try the snapshot backup if you have online JFS installed on your system. Just search the forum for online JFS and snapshot for more info on that.

Hope this helps.

Shumi Begum

Re: DB backup/restore on mirrored disks

I have been doing few steps in order to have a sound database backup without shutting it down.
1) Set up auto archivings on the database.
2) Taking a full database export once a day
3) Taking hot backup of the database.
I am using OMNIback to backup datafiles and archivelogs.
a) it calles a preexec script which i created to start the hot backup mode on every single tablespace. For example
"alter tablespace SYSTEM begin backup;" will set SYSTEM tablespace to hotbackup mode. for your case you create the script which will have command for every single tablesace to put on hot backup mode, so you can backup the whole database.
b) Omniback starts backing up all the datafiles of the database ( such as system01.dbf file )
c) once UNIX level backup is done, execute the post script to end the hot back up mode. ( example, alter tablespace SYSTEM end backup; )
d) also backup the archive logs to a tape.

Note: I had a bad experiance with fbackup command. UNIX fbackup did not get the idea of oracle 's hot backup concept. During the backup, control files and sometime system file were not back up successfully since database was online and people were accessing data, so frecover did not work.
I used omniback and recovered successfully. I did not use oracle RMAN at all. As mentioned, few simple script did the job.

I hope this helps.
harry d brown jr
Honored Contributor

Re: DB backup/restore on mirrored disks


You want to RESTORE without taking the instances down, so this must be a READ-ONLY database?

Why would you need to restore, due to data corruption? Because if it is data corruption, why would you keep the instances up?

If your database isn't being updated by your clients and is simply a READ-ONLY database, then you might be able to get away with RESTORING it to a "mirror" without taking the instances down, but then how are you going to tell the database to use the mirrored copy?

I can understand wanting to put the database into hot backup mode, then splitting the mirrors, then backing up the mirrored copy, then resyncing the mirrors.

I guess I'm confused by the RESTORE question....

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