RE: concepts document part about separating indexes and tablespaces

Mary,
This process is part of on going changes.
I still remember the day when a 64GB striped/mirrored array was thrown at me
when I was looking for 3 logical volumes for my data / index / logs.
Yes I was adamant enough to reject the layout at first glance and took about
a week to test and appreciate the performance.
But on the other side it was 1995 if I remember correctly.
Coming back to the point, what was once a ground rule is not applicable any
more. 
Multiple combination offered by SAN / Disk array makes data index separation
obsolete.
Unless of course if you are supporting some old hardware/software with no
RAID etc.
 
Thanks,
------------------------------------------------------------
PB Singh
DW Architect and Sr Data Modeler
VMware
 
 

________________________________

From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Mary Elizabeth McNeely
Sent: Sunday, May 18, 2008 9:57 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Re: concepts document part about separating indexes and tablespaces



I've gotten into this tiff with storage administrators at many a site.  

 

I have been informed by many of them that the "Oracle approved" disk layout
is separate disks or separate disk pools for table and index access.  (I
could probably find an Oracle document recommending ANYTHING as the approved
way of doing something if I looked long enough.)  I've tried explaining that
we are designing I/O for a multi-user system where I/O on various tables and
their indexes would already be occurring concurrently (as Riyaj suggested
earlier), so I didn't see much point in trying to separate the two.  So,
instead, why don't we "even out" the I/O among the disks by striping what
would have been the table and index disks, together?  

 

I must be some unfortunate combination of not very eloquent, not very polite,
and/or not very persuasive, because the person in charge almost always goes
with what the storage administrators say, considering my idea heretical.  

 

The last time I had this tiff, I lost because the storage administrator was
convinced that if the layout performed poorly, the manufacturer of the disk
array might not support any performance related issues we had, because we had
such a "non-standard" layout (striping tables and indexes in the same
stripe/stripes).  Sigh ...   

MEM

 

----- Original Message ----
From: William Wagman <wjwagman@xxxxxxxxxxx>
To: Mark.Bobak@xxxxxxxxxxxx; ricks12345@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Sent: Thursday, May 15, 2008 3:32:45 PM
Subject: RE: concepts document part about separating indexes and tablespaces



Greetings,

 

I suspect this may date back to the "old days." I remember some years ago a
statement, I believe it was in an Oracle Press book on oracle administration,
that the ideal number of disks for a database was 28 (maybe not that many but
close). This was in days when disks were smaller and performed differently.
The idea was to spread things out across several disks, data, indexes, online
redo logs, archive logs, undo, temp space, etc. so that I/O bottlenecks would
be minimized. With today's faster and bigger (huger actually) disks this is
not only less of an issue but difficult to do. How can you do that on a
machine with 1 500GB disk? Why?

 

Thanks. 

 

Bill Wagman
Univ. of California at Davis
IET Campus Data Center
wjwagman@xxxxxxxxxxx
(530) 754-6208 

From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Bobak, Mark
Sent: Thursday, May 15, 2008 11:27 AM
To: ricks12345@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: RE: concepts document part about separating indexes and tablspaces

 

If it says that, someone should file a documentation bug to get it fixed.

 

-Mark

 

--
Mark J. Bobak
Senior Database Administrator, System & Product Technologies
ProQuest
789 E. Eisenhower, Parkway, P.O. Box 1346
Ann Arbor MI 48106-1346
+1.734.997.4059  or +1.800.521.0600 x 4059
mark.bobak@xxxxxxxxxxxx <mailto:mark.bobak@xxxxxxxxxxxxxxx> 
www.proquest.com <http://www.proquest.com/> 
www.csa.com <http://www.csa.com/> 

ProQuest...Start here. 

 

From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Rick Ricky
Sent: Thursday, May 15, 2008 2:17 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: concepts document part about separating indexes and tablspaces

 

i was talking to someone about this today. I cannot remember where in the
Concepts document that it says that separating data from indexes improves
performances?  

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