Oracle-L: Re: UNIX Raw Devices

From: Phil Vassar <philv_at_CCM.SEIKOTSI.COM>
Date: Mon, 13 Mar 1995 17:23:06 PST
Message-Id: <9503140147.AA10991@alice.jcc.com>

Greetings,

We have a client that insists on raw devices for a large DB we are helping them implement. Having always been File I/O oriented we are not sure of the benefits/drawbacks.

Anyone have a strong feeling one way or the other? And why?

Thanks,
Powel Crosley
Eclipse Technology, Inc.
6410539_at_mcimail.com

pv> Usually raw devices give a performance boost over file systems. Oracle is better at managing the I/O than the O/S. For security reasons you don't have to worry about datafiles being deleted. Increased use of disk space comes to mind the O/S overhead is not included. On large file systems this overhead can be a significant amount of space. If performance and security are primary considerations over maintenance go with raw devices.

Drawbacks include limited backup flexibility... dd being the utility of choice vs tar or cp. Maintenance of raw devices can be more difficult especially if the O/S offers some sort of virtual disk management utility. If the O/S offers virtual disk management then maintenance becomes much easier and flexible using data files. Received on Mon Mar 13 1995 - 20:47:18 CST