Re: alter database suspend

Volker Hetzer wrote:
.
> >
> > Are you using suspend in some of your current processing? Do you have
> > concerns about why it was developed and how it has been placed?
> I'm just curious.
> We use 10g on Linux, one copy of the archivelogs on our netapp filer (nfs).
> Last month we had a controller crash on the database (we could recover
> complety) and since then we think of mirroring some stuff on a netapp
> filer. We started out with the archivelogs, no snapshots, to get a feel
> for it.
> The question for me is, can we make use of the snapshotting capabilities
> in some way?

Still confused here. Usually snapshotting is done in a vendor proprietary way from within a storage device ( set of storage devices ).

For instance with EMC you can have BCV's ( snapshots ). You decide when to establish a snapshot, split off a snapshot, or restore from a snapshot. It's done on a hardware level via looking at the blocks/tracks that have changed. All the disk/LUNs are within the EMC including the snapshots

I imagine the netapp snapshot techniques works similarly ... all the stuff has to be in the netapp filer I would imagine?

You seem to be ( perhaps I am not understanding you ) talking about snapshots between the current database storage ( whatever that is ) and a netapp filer?

> I guess, performance aside, it would make sense to have a controlfile on
> the filer, on a separate volume. In case of a crash we could then decide
> to use the current or a previous controlfile.

That's just placing a controlfile on another disk somewhere. Not involving mirroring or snapshots. Or are you talking about some other setup?

> The same reasoning applies to a lesser extent to archived logs, even if
> it is unlikely that arc messes up logs already archived.
>
> Since oracle's backup mode is for tablespaces I guess that suspend
> is for the other files and I'm wondering about the granularity of
> it.

Sounds like a question to submit to oracle support.

> Will suspend guarantee a completely written controlfile?
> Ditto for archived logs?

How exactly are you thinking about using suspend? I still don't quite understand where you are going.

>
> We have no pressing need, since rman works nicely for us.
> But I'd still like to understand it because it always pays
> to know ones options.

I am not aware of any of the rman documentation that documents or recommends using suspend anywhere ( live and learn ). My knowledge of it ( as noted earlier ) involves some vendor's writeup's of using broken mirrors to take backups from. I would question any such documentation and test it thoroughly. Received on Wed Oct 18 2006 - 09:54:56 CDT