Re: Oracle Raw Partitions

Read this from the bottom up - read my direct reply to you comments first at the end. If your still interested as to why you talked 'rubbish' 3 times, read on. If you still don't agree, fine.

A piece of advice: *learn* before you post.

Oracle, IBM, EMC, Sybase, etc., etc. all recommened raw devices for I/O intensive databases. Try reading the documentation that comes with any of those products. I can point out the pages of the Oracle installation manuals for both 7 & 8, if you like, where Oracle suggest the use of raw devices.

If you do a *simple* test, you will see no performance gain from raw partitions, and for a small data set may even see a degradation.

Now, re-run the same tests on a server running multiple database processes, all competing for the jfs filesystem buffer cache. Raw devices will give you high, stable I/O rates; jfs will not, and the degradation is quite dramatic on a heavily loaded system. I know, I've done lots of monitoring and testing in my time, with good quality performance toolkits, and I've watched this happen. And the memory you wasted on jfs cache can be reallocated to Oracle SGA areas.

Raw devices are not the answer to all problems. But the experts certainly don't agree with your assessment - and niether do I.

MotoX.

G.Anbazhagan wrote in message <01bdd1bd$0aea6700$a29e15a5_at_default>...
>Hi ,
>There will be no performance improvement . There will be performance
>degradation. When you use raw partion ,Oracle writes to the device
>directly. If you use file system , it is beffered. The advantage is , when
>power fails , you are sure the data is in the disk. Raw partition only
>provides better recoverabilty.

Rubbish.

>
>Backup is a real pain. You have to use dd ( dump ) . You cannot use file
>system level copying.

Rubbish.

>
>Raw partition is not worth trying...
>

Rubbish.

>regards
>anbu
>
>A. Gordon <aog_at_capgroup.com> wrote in article <35e46366.14946541_at_news>...
>> Has anyone had experience with Oracle raw partitions? If so, I'd
>> appreciate any reactions to them. In particular, I'd like to know:
>>
>> 1. Do they provide any performance gain over file systems?
>>
>> 2. Are they really harder to manage?
>>
>> I've read some literature already; however,
>> personal experiences would be greatly appreciated!
>>
Received on Thu Aug 27 1998 - 10:03:50 CDT