topic Re: Oracle datafile in Operating System - HP-UX

Oracle datafile

Patrick Chim — Thu, 08 Nov 2001 03:35:16 GMT

Hi all,

Many of my friends and former colleagues like to use UNIX filesystem to store the oracle datafile. Is it difficult to use raw device to hold the database ? What is the advantage and disadvantage between them ?

Regards,
Patrick

Re: Oracle datafile

Roger Baptiste — Thu, 08 Nov 2001 04:06:16 GMT

hi,

Each has its advantage/disadvantages and i don't think there will be a clear-cut choice
of one over another.

From a unix admin point of view, i would happy to have just a raw-volume database and
leave the whole business of tuning, tweaking, backing up etc to the DBA. ;-) and that i
think is a key difference.

Performance wise, Raw volumes are supposed to be faster because they unlike filesystems they do not go through an additonal layer. But, with advanced JFS and tweaking FS mount options that gap is narrowed.

On the backup front, raw volumes would need
backup tools , unlike filesystem which can be accessed/backed up as any other file. But, given the complexity and size of databases, a backup tool (omniback, Rman etc..) is anyway guaranteed to be there.

-raj

Re: Oracle datafile

Scott Van Kalken — Thu, 08 Nov 2001 05:22:51 GMT

I would agree with Raj, it's a matter fo speed. From another admin point of view, it's easy. We don't need to worry about them.

Raj is right, the filesystem option is slower because it communicates directly with the raw device.

I have seen to occasional problem if / when firmware is loaded and oracle is not patched approriately, but this is rare.

Re: Oracle datafile

Animesh Chakraborty — Thu, 08 Nov 2001 05:38:32 GMT

Hi,
When using raw device you need consider few things. See the link for details:

http://forums.itrc.hp.com/cm/QuestionAnswer/1,11866,0xb1e8660142b2d5118ff10090279cd0f9,00.html

Regards
Animesh

Re: Oracle datafile

Thierry Poels_1 — Thu, 08 Nov 2001 08:04:51 GMT

Hi,

the discussion about raw device files or filesystem datafiles has been going on for ages. They both have theire advantages and disadvantages.
Raw device files are theoretically faster, but in the last years the difference has become much smaller (vxfs, Veritas Oracle filesystems!!).
Filesystem datafiles are much easier to handle, you can play around with them just like plain files.
Your choice should probably depend on the size of database, speed of disksystem, type of server, experience of DBA & sysadmin, ...

Have a look at Ixora (pro raw devices)
http://www.ixora.com.au/tips/creation/raw_datafiles.htm

good luck,
Thierry.