Re: switch from file system to raw device

Hans Forbrich wrote:

> Igor wrote:
>

>> Hello,
>> anyone has an idea, whether I can switch datafiles of Oracle (8.0.6)
>> from file system to raw device (raw logical volume in AIX, e.g.)?
>> Any documentation?
>> 
>> Thanks a lot and best regards,
>> Igor

You'd better be able to! There is a large chunk of documentation about how one converts a single-instance database to a RAC. And, of course, the primary requirement with RAC is to have the "data files" on a shared hard disk... and traditionally, because of the lack of cluster file systems, those shared hard disks were raw.

Therefore, in the 9i documentation at least (haven't checked the 10g stuff) there's a large chunk of stuff that's all about how you move *existing* files off a file system onto a raw device.

Oh... and the training material tends to say, use RMAN, because it has no trouble whatsoever backing up off a file system and restoring to a raw partition.  

> However creating a new tablespace that has datafiles in raw partitions,
> moving the tables, and dropping the original tablespace is always a
> possibility (except for system tablespace).

Given he's on 8.0, that's going to be an extremely long-winded way to go about this (no 'alter table X move', for example).

> Of course a potentially 'better' solution would be to create a 9i or 10g
> database and transport the data (probably using exp/imp). But we all
> understand there are thousands of reasons for not moving to a supported
> version of the database.
>
> However, it's not necessarily a good idea to switch. This day and age,
> many file systems are fast enough that the supposed performance advantage
> of raw
> is minimal. (I've even heard 'negative'). Probably although worth
> investigating though.
>
> Check metalink for other notes. ;-Q

Agree with your other comments, 100%.

Regards
HJR Received on Wed Sep 15 2004 - 09:12:00 CDT