Re: ORACLE datafiles on mirrored disks

ea7_at_informatik-zentrum-bayern.de (Michael Kiesel) wrote: ..
> I would like to know if there is anybody out there running ORACLE V7.x
> on mirrored disks.
 ..
> Backup is done by 'unmounting'
> the mirrored disk, copying to tape and 'mounting' it again.
>

I use some mirrired file systems on a Sequent to provide high availability for select tablespaces/instances etc.

All my redo logs and redo log archives are also on mirrored volumes. This works quit well and has acted to preserve the integrity of my databasase on one occasion. (one faild disk out of 20 in 2 years ain't to bad )

For performance, you will want to segrigate your redo logs from your archives (if you use them) from your database files. They shoud all be on seperate disks and on seperat I/O channels if possible.

You can accomplish backup as you suggeset. You will need to either shutdown the database befor you break the mirror or put it in backup mode if you run the database in archive log mode. Then you can break the mirror and bring the database backup/end backup mode.

I cannot speak for other systems, but on Sequent, if you are running your databse in file systems backing up in this fasion is not recommend for Hot backups. There is a chance that the backup will not be recoverable. It is safe if you use raw file systems.

Please test the hot backup technique before relying on my advice. I have not actually performed one.

Hope this helps

1. Paul Singer