Re: DBFS and Oracle File system and dataguard

Responses inline

On Tue, Mar 24, 2020 at 12:55 PM Andrew Kerber <andrew.kerber_at_gmail.com> wrote:

> First, all the examples for setting up DBFS talk about setting it up in
> its own database. Is it mandatory to configure it in a single use database?
> Or is there some advantage to doing that? I suppose one would be so you
> dont have to shut it down every time you start your other database, but are
> there other reasons?
>

If you're planning on mounting the DBFS file store as a filesystem on the database server, I think you'll want a separate database. You'll be setting up a cluster resource for the dbfs mount and it will have start- and stop dependencies. You don't want "crsctl stop resource dbfs_mount" to stop the DBFS database if it is also hosting things other than the DBFS mount.

If you're just planning on accessing the store via remote dbfs_clients, I don't think you'll have that problem. It's effectively the same thing as having database users connecting to a database and reading and writing BLOBs.

Overall I don't think it is mandatory to have a separate database just for DBFS. All of the DBFS functionality is isolated via tablespaces and quotas, DBFS file stores, and users and service accounts with specific permissions, so there is the ability to fully segregate it from other activity in the database.

I saw an article referencing something called and Oracle File System (OFS).
> I cant find reference to that except in one place. Can someone point me to
> documentation on that if it exists.
>

Isn't that just the service that exports the DBFS filesystem for mounting via NFS? 12.2 doc here:
https://docs.oracle.com/en/database/oracle/oracle-database/12.2/adlob/oracle-file-system.html

> Finally, I plan to put the DBFS system in dataguard. I dont see any reason
> why I couldnt, just copy the OS configuration and otherwise set up standard
> dataguard. Is there any reason why I coudn't do that?
>

Assuming you don't intend to mount the DBFS filesystem on the standby site unless the standby database is switched over to primary mode, I don't see why that wouldn't work. But any remote clients that are using the service would need to switch to the standby hostname in the event of a failover or switchover.

You could also run a standalone DBFS setup at your standby site and rsync between the primary site and it. That is the strategy I chose when I was working with DBFS. The benefit is that you don't need to worry about service dependencies between sites, because they're independent between the sites. And you have a little more flexibility in storing files that are unique to the standby site in there.

Andy

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