Re: FileSystem to raw device. Performance will Improve?

krader_at_sequent.com (Kurtis D. Rader) writes:

>Nalini Vallampati <nalini.vallampati_at_daytonoh.attgis.com> writes:
>
>>You can call Oracle and ask for a paper called
>>"Making the Decision to use UNIX Raw Devices"
>>by Cary V.Millsap
 

>>(No.2 in the Oracle NPST Monograph Series)
 

>>This gives a good insight into whether or not UNIX raw devices are
>>appropriate for your site. This paper talks about the confusion about
>>the performance gains that you have when you use raw devices.
 

>>Nalini
>
>Just be aware that most authors have biases that are seldom clearly
>stated. I've been providing advice on tuning matters for several years
>to customers of my present employer. In the past two years I have
>visited somewhere on the order of 20 joint Sequent/Oracle customers.
>Oftentimes an Oracle consultant had recently been onsite. In every such
>instance the Oracle consultant had convinced the customer that raw
>volumes should not be used. I've spoken with other tuning consultants
>in my company and they all report the same thing.
>
>The bottom line is that while I hold Oracle Consultants in high
>regard they appear to have a rather pronounced bias for filesystem
>based batabases. Read the paper cited by Mr. Vallampati with a
>critical mind (always good advice; of course :-)
>--
>Kurtis D. Rader, Sr. Technical Consultant voice: 503/578-3714
>Sequent Computer Systems fax: 503/578-5453
>15450 SW Koll Parkway, M/S WIL1-541 UUCP: ...uunet!sequent!krader
>Beaverton, OR 97006-6063 Internet: krader_at_sequent.com

        First of all, I am an Oracle consultant. Thanks for holding us in high regard. :)

        Second of all, given a choice between using raw Devices and file systems, I would choose file systems any day. The reasons are obvious. Ease of use, administration and a host of other reasons. Managing Raw Device Unix systems is a problem even for experienced UNIX administrators. The performance you can squeak out using raw devices is most often than not offset by the cost of reliability and administration of such systems.

        The bottom line is that if you have an experienced UNIX admin guru in your shop who is willing to take on the pains associated with managing raw devices, use'em by all means. Oracle provides suuport for that.

        Needlesss to say, one should read the obove cited paper before making that decision. Cary Millsap is the father of OFA ( Optimal Flexible Architecture) which has become the de facto standard for Oracle database implementations. We at Oracle hold him in high regard and I am sure Mr. Rader does the same too.

Thanks
Mahesh Vallampati
Staff Consultant
Oracle Services,
Houston, TX
mvallamp_at_us.oracle.com          Received on Mon Oct 30 1995 - 00:00:00 CET