Re: Should we use Raw partitions or Unix File Systems???

John,
This question seems to be popping up a lot these days as people try to decide whether using raw devices will help speed i/o, especially in large databases.

More and more, Unix vendors are making it easier to deal with raw devices, but they can still be something of a hassle compared with file systems. As you probably know, the biggest drawback to the standard file system is the i/o buffer built into the system. It tends to duplicate and work against Oracle's buffering techniques. However, you need to keep in mind the fact that the file systems are also becoming more advanced and there is not as large a gain by going to raw devices as there once was. You have to decide where the trade-off point is

I generally tend to avoid raw devices unless I need every ounce of power I can possibly suck out of a system. I just don't think the increase in throughput is large enough to justify going to raw devices in most cases. Raw devices require extra attention by the DBA's and they also tend to remove some of the options a DBA has for recovering data files. I personally don't think the small gains you MIGHT get in performance are worth the price you pay for using raw devices. I know I will get arguments over this issue, but this tends to be an almost personal decision.

I think you should read the Oracle documentation about using raw devices, as they discuss some of the pros and cons of going that direction. Once you are aware of consequences of choosing raw or file system, you can weigh the choice according to the requirements of your particular database.

Best of luck to you!

Stephen A. (Tony) Rodgers
Prominence Consulting, Inc.

jmj22026_at_glaxowellcome.com wrote in article <3290A303.3265_at_glaxowellcome.com>...
> We are getting two new HP servers. These machines are
> supposed to be top of the line. 1GB ram, 64 bit machines,
> storage array with 20 disk, and 2 CPU's. One of our DBA's
> wants to use Raw Partitions. Is any one using this or has
> any one investigated the ups and downs of using RAW vs Unix
> File Systems. Any input would be greatly appreciated. I
> have only heard negative things, but am open to suggestions
> or ideas. Please either post back to news group or send to
> jmj22026_at_glaxowellcome.com Thanks!!
>
>
> John Jones
> Oracle Consultant
> jmj22026_at_glaxowellcome.com
>
Received on Sat Nov 30 1996 - 00:00:00 CET