Re: JFS on HPUX?

The nature of Oracle writes is such that you do not lose 'pending writes'. A database change is committed only if the redo log write has actually been confirmed by the O/S as a real write. (Obviously various hardware devices such as battery backed cache on disks may lie and claim that data is on disc when it is not).

The risk of data loss due to pending writes is therefore no different on JFS/HFS than it is on raw.

JFS is actually faster in most cases than HFS - particularly for writing the archived redo logs. It is quite a good idea to stick to raw for the online redo log, (if you have a very high throughput system) but if you go to JFS, make sure you install the advanced JFS option that allows you to enable direct i/o, otherwise you may find that the redo has to run a read/write cycle to write the redo log in multiples of 4K.

--

Jonathan Lewis
Yet another Oracle-related web site:  http://www.jlcomp.demon.co.uk

Kevin Brand wrote in message <8dneag$pg3$1_at_news.gte.com>...


>

>I'm trying to decide whether to use Journaled or non-Journaled filesystems

>on HPUX for the Oracle RDBMS datafiles.

>

>Most all of my previous Oracle builds have used raw device files, so using

>the filesystem for datafiles is unfamiliar territory.

>

>My concern is that a power failure or other system crash would cause

 pending


>writes to be lost if I use HFS as opposed to JFS for both the datafiles and

>the redo logs, which would not be a good thing.  On the other hand, using

>JFS could limit write performance.

>

>Are these assumptions correct and what is the general feel of those of you

>versed in using Oracle on HP?

>

>Thanks,

>

>-Kevin

>

>