Re: Oracle 8i for unix mount points

Yes, writes may be expensive on RAID-5, but they happen in the background. The reads are done in the foreground. That means that the read time will influence the end-user performance. Not so much the writes.

Also people may think that they want performance, but what they really want is reliability and recoverability. The question is not IF a disk will fail but WHEN it will fail ! So it is better to accomadate for that, especially for larger databases !

Performance is important but there are more important things ....... so look at the whole picture ....

Anjo

rcordingley_at_my-deja.com wrote:

> If you want to get good performance, you WON'T use RAID5 with Oracle.
> Oracle tends to write in small chunks, and on RAID5, the full "stripe"
> must be read, updated, re-CRCd, and rewritten. This slows things down
> significantly. Disk is cheap, so stripe and mirror (RAID 0+1). That
> was you'll have full redundancy, only take a small performance hit on
> writes, and probably gain a significant amount of perfomance on reads.
>
> If you don't care about that, then don't worry about mount points at
> all, really. Put everything in one big yucky directory. The only
> reasons for multiple mount points are summarized by another respondant.
>
> In answer to your *actual* question: symlinks work just fine for oracle.
>
> Robert
>
> In article <x5u2rfaswj.fsf_at_aeria.phil.uni-erlangen.de>,
> Mac Schwarz <mac_at_phil.uni-erlangen.de> wrote:
> > Hi,
> >
> > I'm going to install Oracle 8i on SUN Sparc Solaris 7 in a few
> > days. The SUN is used for other purposes already and it would be
> > difficult to change the configuration to match the requirements of
> > Oracle now. Normally I would install the db software in /opt/oracle
> > and the databases in a subdirectory of our RAID5.
> >
> > However in the installation manual and the appendix of the
> > administrator's reference another layout is recommended. There should
> > be at least two mount points for the db software and the
> > databases. For the OFA four mount points would be better. These mount
> > points should be named with a char and a fixed-length key (e.g. /u01,
> > /u02, /u03 and /u04).
> >
> > As I wrote above this would require a lot of changes on the existing
> > system. The RAID partition is already mounted under another
> > name. Would a symbolic link to a subdirectory of the RAID (e.g. /u02
> > -> /raid/u02) suffice?
>
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Received on Fri Jul 09 1999 - 02:25:10 CDT